Question

Fungsi f:R ⇒ R dan g:R⇒R ditentukan oleh g(x) = dan (fog)(x) 2 , maka f(x) sama dengan.......

a. x-3
b.x+3
c.2x3
d.2x²-3
e.x²+3


pakai caranya ya

Answer 1

(fog)(x) = 2x² - 1
f(g(x)) = 2x² - 1
f(x²+1) = 2x² - 1
f(x²+1) = 2x² + 2 - 3
f(x²+1) = 2(x²+1) - 3
f(x) = 2x - 3

Answer 2

(fog)(x) = 2x² - 1
f(g(x)) = 2x² - 1
f(x²+1) = 2x² - 1

misalkan t = x²+1 maka x = √t-1

f(t) = 2(√t-1)² -1
     = 2(t-1) - 1
     = 2t -2-1
     = 2t - 3
f(x) = 2x-3