Upgrade to access all content for this subject

Which of the following are equivalent to $\cfrac{d}{dx} (\sin x)$?

I. $y'$ when $y=\sin x +\cos \pi$II. $\cfrac{dy}{dx}$ when $y-\cos x \cdot \tan x = 15$III. $f'(x)$ when $f(x)=\sin x(\cos^2 (3x) + \sin^2 (3x))$

I only

I and II only

I and III only

I, II, and III