Soal fungsi g(x) = 1/x2+1 , (fog)(x) = -2x2-1/x2+1 , maka f(x) adalah

FungSi KomPosiSi

g(x) = 1/(x² + 1)
a = 1/(x² + 1)
x² + 1 = a
x² = a - 1

f(g(x)) = (-2 x² - 1) / (x² + 1)
f(a) = (-2(a - 1) - 1) / a
f(a) = (-2a + 1)/a

Maka,
f(x) = (-2x + 1)/x ✔