Answer
False
Work Step by Step
A transformation is said to be linear if $T(av+w)=aT(v)+T(w)$, for all $ v,w$ in the given domain and for all scalars $a$.
Observe that
$D_x(sin(2x))=\displaystyle \frac{d(sin(2x))}{dx}=2cos(2x)$
and
$2D_x(sin(x))=2\displaystyle \frac{d(sin(x)))}{dx}=2cos(x)$
We see that
$D_x(sin(2x))=2{ }cos(2x)\neq 2cos(x=2D_x(sin(x)))$
Hence, the statement is false.