Question

The function y=sin x + cos x is a solution to which differential equation a. Y+dy/dx =2sinx, b. Y+dy/dx=2cosx or c. dy/dx-y=-2sinx?

Answer 1

b.

Explanation:

If `y=sinx+cosx` then `dy"/"dx=cosx-sinx`.

So `y+dy/dx=sinx+cosx=cosx-sinx=2cosx`.

Thus b. is the correct answer