#### Answer

$r'=\frac{cos((2θ)^{1/2})}{(2θ)^{1/2}}$

#### Work Step by Step

Rewrite the equation: $r=sin((2θ)^{1/2})$
Take the derivative of the equation using Trigonometric derivative and Chain Rule:
$r'=cos((2θ)^{1/2})\times\frac{1}{2}(2θ)^{-1/2}\times2$
$=\frac{cos((2θ)^{1/2})}{(2θ)^{1/2}}$