Question

Please jawab ya ini penting saya ga ngerti...

Grafik fungsi y = 3x^2 - 2nx + n, n >0 mencapai nilai maksimal di titik ( P, -2/3 ). Nilai P adalah....

a. 2
b. -1/3
c. 2/3
d. -2/3
e. 1/3

Answer 1

Y = 3x² -2nx + n
maksimal di (P,-2/3)
berarti :
x = 2n/6 = n/3
x = P = n/3
-2/3 = 3(n/3)² - 2.n.(n/3) + n
-2/3 = 3(n²/9) - 2n²/3 + n
-2/3 = n²/3 - 2n²/3 + n
-2/3 = -n²/3 + n
2 = n² - 3n
n² - 3n - 2 = 0
n = 3+-√(9+8)/2
n = (3+√17)/2
atau n = (3-√17)/2
n > 0, berarti
n = (3+√17)/2
x = p = n/3
p = (3+√17)/2 / 3
p = (3+√17)/6
p = 1/2 + √17/6