Verified answer

Ответ:

a) -2

б) 1/2

Объяснение:

a)

(3cos(2π-B)-sin(π/2+B))/2cos(B-π)

(3cos(B)-cos(B))/-2cos(B)

2cos(B)/-2cos(B)= -2

б)

(2sin(a-2π)-3cos(a-π/2))/2sin(a-3π)

(2sin(a)-3sin(a))/-2sin(a)

-sin(a)/-2sin(a)= -1/-2=1/2