SOLUTION: sin3A / sinA + cos3A / cosA = 4cos2A Please to do this using as least steps as possible please?\ Thanks!!

Algebra ->  Trigonometry-basics -> SOLUTION: sin3A / sinA + cos3A / cosA = 4cos2A Please to do this using as least steps as possible please?\ Thanks!!      Log On


   

Question 752182: sin3A / sinA + cos3A / cosA = 4cos2A
Please to do this using as least steps as possible please?\
Thanks!!
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
A=acute angle
sin3A / sinA + cos3A / cosA = 4cos2A
I assume you meant to write given expression as follows:
sin%5E3%28A%29%2Fsin%28A%29%2Bcos%5E3%28A%29%2Fcos%28A%29=4cos%5E2%28A%29
sin%5E2%28A%29%2Bcos%5E2%28A%29=4cos%5E2%28A%29
1=4cos%5E2%28A%29
4cos^2(A)=1
cos^2(A)=1/4
cos(A)=1/2
A=60º or π/3