Question

Sin 5pi/14 cos pi/7+5pi/14 sin pi/7

Answer 1

Sin 5pi/14 cos pi/7+5pi/14 sin pi/7 = sin(5pi/14 + pi/7) = sin 7pi/14 = sin pi/2 = 1

по формуле: sin(x+y) = sinxcosy + cosxsiny