jika f(x) = x² +2x +2, untuk x ≠ -1, maka f⁻¹(x) = ···

Misalkan
y = x^2 + 2x + 2 = (x+1)^2 + 1
y - 1 = (x+1)^2
x+1 = +- akar (y-1)
x = +- akar (y-1) - 1
f^-1(x) = +- akar (x-1) - 1

[tex]\displaystyle y=x^2+2x+2\\y=x^2+2x+1+1\\y-1=x^2+2x+1\\y-1=(x+1)^2\\\sqrt{y-1}=x+1\\\sqrt{y-1}-1=x\\\boxed{\boxed{\sqrt{x-1}-1=f^{-1}(x)}}[/tex]