# Calculus 6

Calculus Level 5

If $$\, y=cos^{-1}\sqrt{\dfrac{\cos{3x}}{\cos^3{x}}} \,$$ then $$\, \dfrac{dy}{dx}=\sqrt{\dfrac{a}{\cos{bx}+cos{dx}}}$$,

where $$\sin{x}>0$$. Find the value of $$a+b+d$$.

×