Question

If ƒ(𝑥)=𝑥2+1,𝑡ℎ𝑒𝑛(ƒ∘ƒ)(𝑥)=

(A) 2𝑥2+1
(B) 2𝑥2+2
(C) 𝑥4+1
(D) 𝑥4+2𝑥2+1
(E) 𝑥4+2𝑥2+2

Answer 1

(f◦f)(x) = f(f) = f^2+1 = (x^2+1)^2 + 1