State the following trigonometric identities:

MATHEMATICS · Multi-part · A Level · Mathematics · Trigonometry · Trigonometry

Problem

State the following trigonometric identities: (i) The expression for

\sin(x+y)

in terms of

\sin x,\;\cos x,\;\sin y

and

\cos y

. (ii) The expression for

\cos(x-y)

in terms of

\sin x,\;\cos x,\;\sin y

and

\cos y