How do you simplify sin(tan^-1(4x))?

$\frac{4 x}{\sqrt{16 {x}^{2} + 1}}$
Let $a = {\tan}^{- 1} \left(4 x\right)$ in Q1 or Q4., wherein, like tangent, sine is
The given expression is $\sin a = \frac{4 x}{\sqrt{16 {x}^{2} + 1}}$.