Derive cos (2x - 1)

Step-by-step explanation:

I believe that what you want to do here is to "differentiate" cos (2x - 1).

We must use the rule for differentiating cos x and also the chain rule, since the input to cos x here is (2x - 1).

(d/dx) is the derivative operator.

(d/dx) (cos x) = - sin x

(d/dx) cos (2x - 1) = - sin (2x - 1) * (d/dx) (2x - 1) = - sin (2x - 1) (2) = - 2sin (2x - 1)