Question

Find fg(x)

Answer 1

\[f(x)=4x^2+x^4\]
\[g(x)=\sqrt{x^2+4}\]

Answer 2

f(x) = 4x^2 + x^4
f(g(x)) = 4( g(x) )^2 + ( g(x) )^4 ----- (1)
put g(x) = (x^2 + 4)^1/2 into the right hand side of (1) and simplify.