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