Question

If sin ( A-B ) = sinA cosB - cosA sinB and cos ( A-B ) = cosA cosB + sinA sin B. Find the value of sin 15 degrees

Answer 1

let A=45° and B=30
sin(45°-30°)=sin45°cos30°-cos45°sin30°
sin(15°)= 1/√2×√3/2-1/√2×1/2
=√3/2√2-1/2√2=(√3-1)/2√2