Question

найдите 4cosa если sina = -0,5

Answer 1

4 cos a= 4 sqrt(1 - sin ^2 a)=3

Answer 2

cosa =± √ (1-sin²a) = ± √ (1 - ¼ ) = ±√¾ = ± √3/2

4cosa = 4 ·(± √3/2) =±2√3