Applications of acosx + bsinx Given any expression of the form a cos x + b sin x it is better to rewrite it into one of the forms k cos (x ± α) or k sin (x ± α) before answering the question.

It's good to know that to solve any trigonometric equation involving sin 2 x and either sin x or cos x, the process is the same. Replace sin 2 x with 2 sin x cos x, take all the terms to one side ...