Answer
$L(x)=x$ and $Q(x)=x$
Work Step by Step
Differentiate the given function $f(x)$ as follows:
$f'(x)= \sec^2 x ; \\f''(x)= 2 \sec^2 x \tan x$
and $f(0)=0; \\ f'(0)=1; \\ f''(0)=0$
Therefore, $L(x)=f(0)+xf'(0)=x$ and $Q(x) =f(0) x +xf'(0) +\dfrac{x^2f''(0)}{2!}=x$