17cos(a+b)+sinb, если sina=8/17,cosb=4/5, 0

Question

17cos(a+b)+sinb, если sina=8/17,cosb=4/5, 0

Answer 1

Cosa=√1-64/289=√225/289=15/17
sinb=√1-16/25=√9/25=3/5
17cos(a+b)+sinb=17cosacosb-17sinasinb+sinb=17*15/17*4/5-17*8/17*3/5+3/5=
=12-4,8+0,6=7,8