Question:
Let $f: \mathrm{R} \rightarrow \mathrm{R}$ be such that for all
$x \in R\left(2^{1+x}+2^{1-x}\right), f(x)$ and $\left(3^{x}+3^{-x}\right)$ are in A.P., then the minimum value of $f(x)$ is
Correct Option: , 2
Solution:
$f(x)=\frac{2\left(2^{x}+2^{-x}\right)+\left(3^{x}+3^{-x}\right)}{2} \geq 3$
(A.M $\geq$ G.M)