Cos107*cos17+sin107*sin17= cos36*cos24-sin36*sin24= sin63*cos27+cos63*sin27= sin51*cos21-cos51*sin21=

Формулы (синус и косинус суммы и разности):

1) cos107*cos17+sin107*sin17= cos(107-17) = cos90 = 0

2)  cos36*cos24-sin36*sin24= cos(36+24) = cos60 = 1/2

3)  sin63*cos27+cos63*sin27= sin(63+27) = sin90 = 1

4)  sin51*cos21-cos51*sin21=  sin(51-21) = sin30 - 1/2