Fungsi Kuadrat dan Menggambarkan Parabolanya

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Tentukan Koordinat titik puncak dan parabola terbuka ke atas dan kebawah

Gambarkanlah Parabolanya !

1.      Y = x² – 4                                                       

(x -2) (x+2)

x – 2 = 0          x+2 = 0                                               

x = 2                x = -2

(2 , 0)                 (-2 , 0)

Titik sumbu y 

y = x² – 4                   

x = 0 -> y = 4                                                                        

(0 , 4)     

                                   

           

Titik Puncak                                                               

x = -b ÷ 2.a                  y = x² – 4        

x = -0 ÷ 2.1                 y = 0² - 4

x = 0 ÷ 2                      y = -4

x = 0

                        (0 , 4)

Gambar Parabola soal no 1

2.      y = 16 – 4x²

(-2x + 4) (2x + 4)

-2x + 4 =0       2x + 4 = 0

x = -2               x = 2                                                 

(-2 , 0)               (2 , 0)

Titik Sumbu Y

y = 16 – 4x²

x=0 -> y = 16

(0 , 16)

                                                                                               

Titik Puncak

x = -b ÷ 2.a                  Y = 16 – 4x²

x = -0 ÷ 2.4                 y = 16 – 4.0

x = 0 ÷ 8                      y = 16

x = 0

                        (0 , 16) 

Gambar Parabola soal No 2

3.      Y = x² – 4x +4

a = 1 b = -4 c = 4

(x - 2 )                         (x-2 )                                                              

x - 2 = 0           x - 2 = 0

x = 2                x = 2                                                               

(2 , 0)               (2 , 0)

                                                                                                           

Titik sumbu Y

y = x² – 4x +4

x = 0 -> y=4

            (0 , 4)

Titik Puncak

x = -b ÷ 2.a                 y = x² – 4x + 4

x = 4 ÷ 2.1                  y = 2² – 4.2 + 4

x = 4 ÷ 2                     y = 4 – 8 + 4

x = 2                           y = 0

                        (2 , 0)

Gambar Parabola soal no 3

4.      y = 4x² -8x -12

a = 4 b = -8 c -12

(2x + 2 )          (2x – 6)

2x + 2 = 0        2x – 6 = 0

x = 1                x = -3

(1 , 0)               (-3 , 0)

Titik Sumbu Y

y = 4x² – 8x – 12

x = 0 -> y = -12                                                        

(0 , -12)

Titik Puncak

x = -b ÷ 2.a                  y = 4x² – 8x - 12

x = 8 ÷ 2.4                   y = 4.1² – 8.1 -12                        

x = 8 ÷ 8                      y = 4 – 8 - 12

x = 1                            y = -16                                       

                        (1, -16)

 Gambar Parabola Soal No 4