Answer:
f(f(x)) = x⁴ + 2x² + 2
Step-by-step explanation:
if f(x) = x² + 1, then f(f(x)) is equal to:
f(x)² + 1
= (x² + 1)² + 1
= x⁴ + 2x² + 1 + 1
= x⁴ + 2x² + 2
