Question

If f(X)=X2+1 find fof

Answer 1

given

f(x)= x^2 + 1

find

fof means

f(f(x))

so

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

= x^4+1^2+2.x^2 + 1

= x^4 + 2x^2+2

hence

fof= x^4 + 2x^2+2