Function $f(x)=\frac{\left(1+2^x\right)^9}{2^x}$ is :

even odd neither even nor odd None of these

neither even nor odd

$f(-x)=\frac{\left(1+2^{-x}\right)^9}{2^{-x}}=\frac{\left(2^x+1\right)^9}{\left(2^x\right)^8} \neq f(x)$ or $-f(x)$ Hence f(x) is neither even nor odd Hence (3) is the correct answer.