SOLUTION: Simplify the expression by using a double-angle formula. cos^2 (3pi/11) - sin^2 (3pi/11) Please let me know if this is correct: I think this is an identity problem. co

Algebra ->  Trigonometry-basics -> SOLUTION: Simplify the expression by using a double-angle formula. cos^2 (3pi/11) - sin^2 (3pi/11) Please let me know if this is correct: I think this is an identity problem. co      Log On


   

Question 967615: Simplify the expression by using a double-angle formula.
cos^2 (3pi/11) - sin^2 (3pi/11)

Please let me know if this is correct: I think this is an identity problem.
cos (2A) = cos^2 A - sin^2 A
would the expression simplify to:
cos(2 (3pi/11))



Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Simplify the expression by using a double-angle formula.
cos^2 (3pi/11) - sin^2 (3pi/11)
Please let me know if this is correct: I think this is an identity problem.
cos (2A) = cos^2 A - sin^2 A
would the expression simplify to:
cos(2 (3pi/11)) =6pi/11
you got it correct