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Published by mark.22827, 2021-05-26 14:29:49

เอกสารประกอบการเรียน เรื่อง ความสัมพันธ์และฟังก์ชัน



3.2 ฟงกชนก าลังสอง (quadratic function)


จุดมุงหมายของกิจกรรม

กิจกรรมน้ใช้เพือเสรมความเข้าใจของนักเรยนเกียวกับกราฟของฟงก์ชันก าลังสอง






ขันตอนการด าเนนกิจกรรม


1) ให้นักเรียนจับคู่กัน จากนั้นเปิดเว็บไซต์ ipst.me/10304 หรือสแกน











2) ให้นักเรยนแต่ละค่ลากปมบนสไลด์ a, h และ k


2
เพือส ารวจกราฟของฟงก์ชัน ( ) = ( − ℎ) + ; , ∈ ℝ
แล้วตอบค าถามต่อไปน้ ี






ปม a ปม h ปม k ลักษณะกราฟ
กรณี a > 0 เซตค่า h = 0 เซตค่า k = 0




(เลอนให้มากข้นหรอน้อยลง)

กรณี a < 0 คงท ี่ คงท ี่




(เลอนให้มากข้นหรอน้อยลง)




กรณี a > 0 คงท ี่ (เลอนให้มากข้นหรอ



คงท ี่ น้อยลง)
กรณี a > 0 (เลอนให้มากข้นหรอ คงท ี่




คงท ี่ น้อยลง)
กรณี a < 0 คงท ี่ (เลอนให้มากข้นหรอ




คงท ี่ น้อยลง)
กรณี a < 0 (เลอนให้มากข้นหรอ คงท ี่




คงท ี่ น้อยลง)


3) ร่วมกันอภปรายผลการส ารวจ






ิ์






เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)













ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.

ห น้ า | 48


หรอหาจาก


ℎ = (− )
2


คณิต




ฟงก์ชันพาราโบลาในรป ( ) = + + มจดวกกลับ คอ (− , 4 − 4 2 )

2
2 4 เพิ่มเติม
จัดรป



โดยวิธก าลังสองสมบรณ ์


( ) = ( − ℎ) + มจดวกกลับ คอ (ℎ, ) คณิต

2

พ้นฐาน

ตัวอยางที่ 24











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ิ์




เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)










ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.




ห น้ า | 49


ตัวอยางที่ 25










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ิ์








เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 50

ตัวอย่างที่ 26

คณิต


เพิ่มเติม


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ตัวอยางที่ 27
คณิต

ื่

จงหาค่าต าสดของ + เมอ + = 16 เพิ่มเติม

2
2

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ิ์





เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)






ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.








ห น้ า | 51



แบบฝกหดที่ 5




















































































ิ์
เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 52









ิ์
เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 53


วิธท า .............................................................................................................
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ิ์



เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 54


วิธท า ........................................................................................................................................................................
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ิ์

เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 55

คณิต

พ้นฐาน




















วิธท า ........................................................................................................................................................................
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ิ์







เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)






ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.








ห น้ า | 56

คณิต

เพิ่มเติม


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คณิต
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ิ์
เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)






ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.








ห น้ า | 57



3.3 ฟงกชนขันบันได (step function)




ฟงก์ชันทมโดเมนเปนสับเซตของเซตของจ านวนจรง และโดเมนถกแบ่งออกเปนช่วงย่อยมากกว่า 1 ช่วง







ตัวอยางที่ 27

















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ิ์
เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 58

แบบฝกหดที่ 6




























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ิ์


เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 59


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ิ์






เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 60

คณิต


พ้นฐาน

















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ิ์







เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)






ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.








ห น้ า | 61

คณิต


พ้นฐาน


















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ิ์







เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)





ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.









ห น้ า | 62






3.4 ฟงกชนเอกซโพเนนเชยล (exponential function)

ื่




ฟงก์ชันเอกซโพเนนเชยลทอยู่ในรป ( ) = เมอ > 0 และ ≠ 1





จุดมุงหมายของกิจกรรม







กิจกรรมน้ใช้เพือเสรมความเข้าใจของนักเรยนเกียวกับกราฟของฟงก์ชันเอกซโพเนนเชยล




ขันตอนการด าเนนกิจกรรม
1) ให้นักเรียนจับคู่กัน จากนั้นเปิดเว็บไซต์ ipst.me/9046 หรือสแกน









2) ให้นักเรยนแต่ละค่ส ารวจกราฟของฟงก์ชัน ( ) = 2 โดย



2.1) คลก ℎ
2.2) สไลด์ปม แล้วตอบค าถามต่อไปน้ ี




ื่


 เมอ เปลยนจากน้อยไปมากค่าของ ( ) เปลยนแปลงอย่างไร
...........................................................................................................................................................






ื่
 เมอ เปนจ านวนจรงบวกและเพิ่มข้น ค่าของ ( ) เปลยนแปลงอย่างไร
...........................................................................................................................................................



ื่

 เมอ เปนจ านวนจรงลบและลดลง ค่าของ ( ) เปลยนแปลงอย่างไร
...........................................................................................................................................................







ื่


3) ให้นักเรยนแต่ละค่ส ารวจกราฟของฟงก์ชัน ( ) = เมอ เปนค่าอน ๆ ทไม่ใช่ 2 แล้วใช้ค าถามข้อท ี ่

2.2) สังเกตการเปลี่ยนแปลงของ ( )
















ิ์

เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)
ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.















ห น้ า | 63

ตัวอย่างที่ 28




จงเขยนกราฟของ ( ) = 2 , ( ) = 3 และ ℎ( ) = ( ) ในระบบพิกัดฉากเดยวกัน

1


3
x
( ) = 2



x

( ) = 3




x


ℎ( ) = ( )
1
3
















































ิ์

เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 64

ตัวอย่างที่ 29





จ านวนแมลงชนดหนงหาได้จากฟงก์ชัน
( ) = 100(1.3)


ื่
เมอ ( ) แทนจ านวนแมลง (มหน่วยเปนตัว) เมอเวลาผ่านไป วัน




1) จงหาจ านวนแมลง เมอเวลาผ่านไป 0, 1, 2, ..., 7 วัน


2) จงหาจ านวนแมลงทเพิ่มข้นในแต่ละวัน ตั้งแต่วันแรกถงวันท 7







3) จงเขยนกราฟของฟงก์ชัน

วิธท า ........................................................................................................................................................................
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ิ์



เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)






ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.








ห น้ า | 65

แบบฝกหดที่ 7









1. จงเขียนกราฟของฟงกชนตอไปน้ พรอมทังหาโดเมนและเรนจ ์



1

1) ( ) = 3 2) ( ) = ( )
3











3) ( ) = 2 + 1 4) ( ) = 3 − 1















5) ( ) = 2 −1


























ิ์

เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 66








2. ปจจุบันเมองหนงมีประชากร 4,000 คน และมีอัตราการเพิ่มของประชากร 3% ตอป ถาจานวนประชากรในปที่



นบจากปจจุบัน หาไดจาก ( ) = , ( . ) จงหาจ านวนประชากรในอีก 10 ปขางหนา และในอีก








20 ปขางหนา


วิธท า ........................................................................................................................................................................
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ื่


3. ชายคนหนงกูเงนจากธนาคาร 850,000 บาท เพอซอมแซมบาน โดยธนาคารก าหนดอัตตราดอกเบี้ยรอยละ 8 ตอ








ป และคิดดอกเบี้ยแบบทบตนทุกป ถาชายคนน้มีก าหนดชาระหน้ในอีก 3 ปขางหนา และจานวนเงนทีเขาตอง







ชาระคนใหธนาคารหาไดจาก ( ) = , ( . ) เมอ แทนจานวนปทีกูเงน

ื่

















ื่
3.1) จงหาวาเมอครบก าหนดชาระหน้ เขาจะตองชาระเงินคนใหธนาคารเทาใด โดยคิดเปนดอกเบี้ยเทาใด

ื่
3.2) จงเขียนกราฟของ เมอ ∈ { , , , , }

วิธท า ........................................................................................................................................................................
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ิ์







เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 67











สมมตว่าเกิดเหตการณซอมบ้บกโรงเรยน เร่มจากซอมบ้ 5 ตัว บกเข้ามาในโรงเรยน และก าหนดให้ในแต่ละวัน








ซอมบ้แต่ละตัวสามารถแพร่เช้อให้กับผู้ทยังไม่ได้รบเช้อจ านวน 2 คน โดยผู้ทได้รบเช้อจะกลายเปนซอมบ้ด้วย





ขันตอนการปฏิบัติ







1. จากสถานการณข้างต้น นักเรยนคดว่าจ านวนซอมบ้กับเวลามความสัมพันธกันในลักษณะใด
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2. จากสถานการณข้างต้น ให้นักเรยนเตมตารางด้านล่างให้สมบูรณ ์



วันท ี่ จ านวนซอมบ้ (ตัว) วันท ี่ จ านวนซอมบ้ (ตัว)

0 6
1 7
2 8
3 9
4 10
5 11

3. น าข้อมูลในข้อ 2. ไปเขยนกราฟโดยให้แกน X แสดงเวลา(วัน) และแกน Y แทนจ านวนซอมบ้(ตัว)

















4. กราฟทได้ในข้อ 3 มลักษณะเปนอย่างไร เพราะเหตใด

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ิ์





เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)










ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.




ห น้ า | 68




5. เขยนฟงก์ชันแสดงจ านวนซอมบ้ในแต่ละวัน
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6. สมมตประเทศไทยมจ านวนประชากร 69,000,000 คน คนทั้งประเทศจะกลายเปนซอมบ้ภายในเวลาเท่าใด


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7. สมมตจ านวนประชากรโลกมทั้งหมด 7,570,000,000 คน คนทั้งโลกจะกลายเปนซอมบ้ภายในเวลาเท่าใด


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ิ์

เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)






ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.








ห น้ า | 69










ขจรชอบวิชาคณตศาสตรจงเก็บข้อมลต่าง ๆ ในชวิตตนเองโดยใช้กราฟ วันหนงขจรได้หายตัวไป เมอนักสบไปค้น







ทห้องพักของขจร ได้พบกระดาษทมกราฟลักษณะต่าง ๆ จ านวน 6 แบบ และข้อความทคาดว่าเปนค าอธบาย








ประกอบแต่ละกราฟ จ านวน 6 ข้อความ ซงเขยนแยกออกจากกราฟ จงท าให้ไม่สามารถทราบได้ว่าค าอธบายใดค่ ู

กับกราฟใด ดังรป

















































ิ์


เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)












ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.


ห น้ า | 70

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ิ์








เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 71


3.5 ฟงกชนอน ๆ คณิต

ื่

เพิ่มเติม


ตัวอยางที่ 30



จงเขยนกราฟของฟงกชนก าลังสาม ( ) = − 4

3

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x -3 -2 -1 0 1 2 3

y





































ิ์
เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 72

ตัวอยางที่ 31





จงเขยนกราฟของฟงกชนเศษสวนพหุนาม ( ) = และจงพิจารณาว่ากราฟตัดแกน X และแกน Y

1


หรอไม่

วิธท า ........................................................................................................................................................................
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x -10 -2 -1 -0.5 -0.1 0.1 0.5 1 2 10

y



































ิ์




เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 73

ตัวอย่างที่ 32





จงเขยนกราฟของฟงกชนคาบ ( ) = { 4 − , ≥ 2
2 − 2 , < 2

วิธท า ........................................................................................................................................................................
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ิ์








เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 74

ตัวอย่างที่ 33








จงเขยนกราฟของฟงกชนคาสมบูรณ ( ) = | |

วิธท า ........................................................................................................................................................................
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ิ์



เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 75

ื่

เทคนคการเขียนกราฟโดยการเลอนกราฟ คณิต
เพิ่มเติม
















ตัวอย่างที่ 34





































ื่
หมายเหตุ นักเรยนอาจใช้กระดาษลอกลายในการท ากราฟเลอนขนาน















ิ์








เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 76

แบบฝกหดที่ 8












1. จงเขียนกราฟของฟงกชนที่ก าหนดใหตอไปน้ พรอมทังหาโดเมนและเรนจ ์
1) ( ) = + 1
3

วิธท า ........................................................................................................................................................................
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ิ์


เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 77

1
2) ( ) =
+2

วิธท า ........................................................................................................................................................................
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ิ์







เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 78

+ 3 , ≥ 1
3) ( ) = {
2
− 1 , < 1

วิธท า ........................................................................................................................................................................
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ิ์






เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 79

4) ( ) = | + 2|


วิธท า ........................................................................................................................................................................
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ิ์
เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)





ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.









ห น้ า | 80

ื่









2. จงเขียนกราฟของแตละฟงกชนตอไปน้ โดยใชการเลอนขนานในแนวตังหรอแนวนอน
1) ( ) = − 3 2) ( ) = ( + 2) − 3
2
2











3) ℎ( ) = √ − 3 4) ( ) = √ + 1 + 3


















5) ( ) = | − 2| − 5 6) ( ) = | + 3| + 5

























ิ์



เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 81




ื่





3. ในแตละขอตอไปน้ ก าหนดฟงกชน และวิธการเลอนกราฟของ จงเขียนกราฟและสมการของกราฟที่ไดใน


ขนสุดทาย






1) ( ) = , เลอนกราฟข้น 2 หน่วย แล้วเลอนทางขวาอก 3 หน่วย


2
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2) ( ) = , เลอนกราฟลง 1 หน่วย แล้วเลอนทางซ้ายอก 5 หน่วย
3
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ื่

3) ( ) = | | , เลอนกราฟไปทางขวา หน่วย แล้วเลอนกราฟลง 2 หน่วย
1
2
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4) ( ) = | | , เลอนกราฟไปทางซ้าย 1 หน่วย แล้วเลอนกราฟข้น 5 หน่วย




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ิ์

เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)






ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.








ห น้ า | 82








4. การด าเนนการของฟงกชน (ผลบวก ผลลบ ผลคูณ และผลหารของฟงกชน) (พ) คณิต
เพิ่มเติม


บทนยาม 11





ให้ และ เปนฟงก์ชันซงมโดเมนและเรนจ์เปนสับเซตของ ℝ ผลบวก (sum) ผลตาง (different) ผลคูณ



(product) และ ผลหาร (quitient) ของ และ เขยนแทนด้วย + , − , และ ตามล าดับ



เปนฟงก์ชันซก าหนดโดย




( + )( ) = ( ) + ( )
( − )( ) = ( ) − ( )
( )( ) = ( ) ( )
( )
( )( ) = เมอ ( ) ≠ 0
ื่
( )



ตัวอยางที่ 35

ให้ ( ) = + 1 และ ( ) = √
3



1) จงหา + , − , และ พรอมทั้งโดเมนของแต่ละฟงก์ชัน


2) จงหา ( + )(1), ( − )(1), ( )(2) และ ( )(2)


วิธท า ........................................................................................................................................................................
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ิ์








เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)






ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.








ห น้ า | 83


ตัวอยางที่ 36
ให้ = {(1,6), (2,16), (3,12), (5,18)}

และ = {(1,6), (2,11), (3,0), (4,1)}



จงหา + , − , และ พรอมทั้งโดเมนของแต่ละฟงก์ชัน



วิธท า ........................................................................................................................................................................
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ิ์



เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 84



5. ฟงกชนประกอบ คณิต







หากราคาสนค้าเปนฟงก์ชันของต้นทนการขนส่ง ซงต้นทนการขนส่งเปนฟงก์ชันของราคาน ้ามัน เพิ่มเติม






ดังนั้น ราคาสนค้าจงเปนฟงก์ชันของราคาน ้ามันด้วย




ให้ และ เปนฟงก์ชัน ดังแสดงในแผนภาพ



A B C
a p
1

2 b q
3 c r



จากแผนภาพจะได้ (1) = ................, (2) =.............., (3) =....................

( ) = ................, ( ) =.............., ( ) =....................

ให้ และ ทก าหนดให้ จะได้


( (1)) = ................=..............

( (2)) = ................=..............

( (3)) = ................=..............










จะเหนว่าฟงก์ชันทสรางข้นใหม่เปนฟงก์ชันจากเซต A ไป C เขยนแทนฟงก์ชันน้ด้วย ∘ (จโอเอฟ) และ



เรยกว่า ฟงกชนประกอบ (composite function) ของ และ โดย




∘ (1) = ................=..............
∘ (2) = ................=..............
∘ (3) = ................=..............
นั่นคอ ∘ = .....................................................................

บทนยาม 12




ให้ และ เปนฟงก์ชันและ ∩ ≠ ∅









ฟงก์ชันประกอบของ และ เขยนแทนด้วย ∘ คอฟงก์ชันทโดเมนคอ
∘ = { ∈ | ( ) ∈ }


และก าหนด ∘ โดย ∘ ( ) = ( ( )) ; ∀ ∈ ∘

ิ์







เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)






ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.








ห น้ า | 85

ตัวอยางที่ 37





ให้ ( ) = − 3 และ ( ) = + 2 จงหาฟงก์ชัน ∘ และ ∘ พรอมทั้งโดเมน
2

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ิ์



เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 86

ตัวอยางที่ 38





ก าหนด ( ) = − − 1 และ ( ) = √ จะม ∘ และ ∘ หรอไม่ เพราะเหตใด ถ้าม จงหา ∘ และ


2

∘ พรอมทั้งโดเมน

วิธท า ........................................................................................................................................................................
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ิ์

เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 87

ตัวอยางที่ 39




ก าหนด ( ) = √ และ ( ) = จงหา ∘ และ ∘ พรอมทั้งโดเมน
2

วิธท า ........................................................................................................................................................................
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ิ์


เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)





ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.









ห น้ า | 88

ตัวอยางที่ 40



ให้ = {(1,5), (2,4), (3,6)} และ = {(3,8), (4,10), (5,9)} จงหา ∘


วิธท า ........................................................................................................................................................................
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ตัวอยางที่ 41




ก าหนด ( ) = (2 − 3) จงเขยน ให้อยู่ในรปของฟงก์ชันประกอบของฟงก์ชันสองฟงก์ชัน


10

วิธท า ........................................................................................................................................................................
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ิ์





เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 89

แบบฝกหดที่ 9







1. จงหา + , − , และ พรอมทังโดเมนของแตละฟงกชน





1) ( ) = และ ( ) = − 2
2
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2) ( ) = √9 − และ ( ) = √ − 2
2
2
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3) ( ) = + 4 และ ( ) = 3 + 1
3
2
2
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2 4
4) ( ) = และ ( ) = −
+2
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ิ์


เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 90

3) ( ) = √ + 1 และ ( ) = √1 −
2
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1
4) ( ) = และ ( ) =
+2 −1
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2. จงหาโดเมนของฟงกชน
1) ( ) = √ + √2 −
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2) ( ) = √ + 2 −
1

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1
3) ( ) = ( + 2) ( − 4) 4
2
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ิ์








เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 91

√ +5
4) ( ) =
−1
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3. ให ( ) = − และ ( ) = − จงหา

1) ( (0)) และ ( (0))

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2) ( (4)) และ ( (1))

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3) ∘ (−2) และ ∘ (−2)

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4) ∘ (−1) และ ∘ (2)
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ิ์
เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 92


4. ให = {(− , ), ( , ), ( , )}, = {(− , ), ( , ), ( , )} และ = {( , ), ( , )} จงหา



ฟงกชนตอไปน้ ี

ท ี่ ฟงก์ชัน ค าตอบ ท ี่ ฟงก์ชัน ค าตอบ


1 + 7 ∘
2 − 8 ∘

3 − 9 ∘ ℎ
4 10 ℎ ∘

5 11 ℎ ∘

6 12 ∘ ℎ

ื่





5. จงหา ∘ , ∘ , ∘ และ ∘ พรอมทังโดเมนของแตละฟงกชน เมอก าหนดฟงกชน และ ในแต ่






ละขอตอไปน้ ี
1) ( ) = 3 + 2 และ ( ) = 4 − 1
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2) ( ) = และ ( ) = + 5
2
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3) ( ) = และ ( ) = 2 + 3
1

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ิ์

เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)

ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.













ห น้ า | 93

4) ( ) = | | และ ( ) = 2 − 5

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+1
5) ( ) = และ ( ) = 2 − 3

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6) ( ) = √ และ ( ) = √
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6. ก าหนด ( ) = + , ( ) = − และ ( ) = √ จงหา ( ∘ ) ∘ และ ∘ ( ∘ )

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ิ์
เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)








ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.






ห น้ า | 94



ึ่
ื่







7. จงหาฟงกชน และ ซง ∘ = เมอก าหนดฟงกชน ในแตละขอตอไปน้ ี
1) ℎ( ) = ( − 9)
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2) ℎ( ) = √ + 5
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2
3) ℎ( ) =
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1
4) ℎ( ) =
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5) ℎ( ) = |1 − |
5
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ิ์
เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)










ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.




ห น้ า | 95

6) ℎ( ) = √2 + √

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ึ่

8. ถา ( ) = + และ ( ) = + + แลว จงหาฟงกชน ซง ∘ =


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+ , ≤ −
+ , ≤
9. ก าหนด ( ) = { , < < และ ( ) = { , ≥

− , ≥

จงหาคาของ ( ∘ )( ) + ( ∘ )( )
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ิ์



เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)







ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.







ห น้ า | 96



6. ฟงกชนผกผัน

คณิต
ทฤษฎีบท 1 เพิ่มเติม
ให้ เปนฟงก์ชัน


เปนฟงก์ชันผกผัน ↔ เปนฟงก์ชัน 1 - 1













ถ้าตัวผกผันของฟงก์ชัน เปนฟงก์ชัน แล้ว จะเรยก −1 ว่าเปน ฟงกชนผกผัน (inverse function) ของ

ตัวอยางที่ 42


ฟงก์ชัน ซงก าหนดโดย ( ) = 3 + 1 มฟงก์ชันผกผันหรอไม่ ถ้าม จงหาฟงก์ชันผกผัน









วิธท า ........................................................................................................................................................................
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ิ์



เอกสารประกอบการเรยนเล่มน้เปนลขสทธของ นายพัชรพล ชดชม (ครมารค)











ศกษาศาสตรบัณฑต เอกคณตศาสตร มช./ ศกษาศาสตรมหาบัณฑต การบรหารการศกษา ม.กรงเทพธนฯ/ ศกษาศาสตรมหาบัณฑต การสอนคณตศาสตร มก.



ห น้ า | 97


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