Question

If sin (A + B) = sin A cos B+cos A sin B
and cos (A - B) = cos A cos B + sin Asin B,
find the values of (i) sin 15° and (ii) cos 15°

Answer 1

Step-by-step explanation:

sin15°=sin(45-30)

=sin45cos30 – cos45sin 30

= 1 X √3 – 1 x 1

√2 2. √2 2

= √3. – 1.

2√2. 2√2

=√3–1

2√2

similarly do this for cos15°