# SOLUTION: Simplify the expression by using a double angle formula. 2sin((2pi)/(11))cos((2pi)/(11)) I think it may be sin((4pi)/(11)). I am not sure on this and I could use the help.

Algebra ->  Algebra  -> Trigonometry-basics -> SOLUTION: Simplify the expression by using a double angle formula. 2sin((2pi)/(11))cos((2pi)/(11)) I think it may be sin((4pi)/(11)). I am not sure on this and I could use the help.      Log On

 Ad: Algebra Solved!™: algebra software solves algebra homework problems with step-by-step help! Ad: Algebrator™ solves your algebra problems and provides step-by-step explanations!

 Algebra: Trigonometry Solvers Lessons Answers archive Quiz In Depth

 Question 596137: Simplify the expression by using a double angle formula. 2sin((2pi)/(11))cos((2pi)/(11)) I think it may be sin((4pi)/(11)). I am not sure on this and I could use the help.Answer by jim_thompson5910(28503)   (Show Source): You can put this solution on YOUR website!Using the identity 2*sin(x)*cos(x) = sin(2x) we get $\LARGE 2\sin\left(\frac{2\pi}{11}\right)\cos\left(\frac{2\pi}{11}\right) = \sin\left(2\times\frac{2\pi}{11}\right) = \sin\left(\frac{4\pi}{11}\right)$ ----------------------------------------------------------------------------- So $\LARGE 2\sin\left(\frac{2\pi}{11}\right)\cos\left(\frac{2\pi}{11}\right)=\sin\left(\frac{4\pi}{11}\right)$ which means you are 100% correct. Nice job.