A+B= 270 (derajat), cosA=1/2. Tentukan cotanB?

Trigonometri

A + B = 270°

A = 270° – B

cos A = 1/2

cos (270° – B) = 1/2

– sin B = 1/2

sin B = -1/2 → B kuadran III

y/r = -1/2

x = √(r² – y²) = √(2² – (-1)²) = √3

cotan B = x/y = – √3 / -1 = √3