Forty three million, six hundred and four thousand, five hundred ninety four
Answer:
-90 , 30
Step-by-step explanation:
sina = cos(2a)
= 1 - 2(sina)^2
2(sina)^2 + sina -- 1 = 0
( sina + 1 )( 2sina - 1 ) = 0
sina = -1 or sina = 1/2
=> a = -90 degrees or => a = 30 degrees
