differentiate y=sin? cos?

Question

Please help me

Answer 1

y = sinθcosθ

 

Use the product rule to find dy/dθ:

 

dy/dθ = sinθ d/dθ(cosθ) + cosθ d/dθ(sinθ)

 

         = sinθ(-sinθ) + cosθcosθ

 

         = cos² θ - sin²θ

 

         = cos2θ

 

 

Answer 2

Sine (sin) is the length of the opposite side divided by the length of the hypotenuse.

 

 

Cos is the length of the the adjacent divided by the length of the hypotenuse.