Question

Let $f(x)$ be a polynomial function such that $f(x)+f\left(\frac{1}{x}\right)=f(x)\cdot f\left(\frac{1}{x}\right)$ and $f(3)=82$, then the value of $f(5)$, is

• A. 126
• B. 626
• C. 3126
• D. None

Answer 1

Answer: (B)

$f(x)=1+x^4$
$\therefore f(5)=626.$