Answer
$2 \sec^2 x \tan x$
Work Step by Step
We have: $j(x)=\sec^2 x$
We need to differentiate both sides with respect to $x$.
$j^{\prime}(x)=2 \sec x \dfrac{d}{dx} [\sec x]\\=2 \sec x \times \sec x \tan x\\=2 \sec^2 x \tan x$
Therefore, $j^{\prime}(x)=2 \sec^2 x \tan x$
