Mahesh Godavarti
-2

Shrek, can you check your question again and see if you wrote it out properly? Or you can simply attach a picture of the question. I will be able to help you better then.


Typically, these types of problems use the following identities:


  1. 2 sin(A) cos(A) = sin(2A)
  2. cos2(A) - sin2(A) = cos(2A)
  3. sin(A) cos(B) + cos(A) sin(B) = sin(A + B)
  4. cos(A) cos(B) - sin(A) sin(B) = cos(A + B)
  5. 2 sin2(A) = 1 - cos(2A)
  6. sin2(A) + cos2(A) = 1


We have to repeatedly apply these identities till we get a cos or sin that we know the answer to. E.g. cos(180), cos(60) etc.