Это нужно вычислить а)sin73°cos17°+cos73°sin17° б)cos7π/9cos11π/9-sin7π/9sin11π/9

A) sin(a+b) = sinacosb + sinbcosa
sin73°cos17° + cos73°sin17° = sin(73°+17°) = sin90° = 1

Б) cos(a+b) = cosacosb - sinasinb
cos(7π/9)cos(11π/9) - sin(7π/9)sin(11π/9) = cos(7π/9 + 11π/9) = cos2π = 1