SOLUTION: I don't really know the topic. Which expression is equivalent to sin(2x) − sinx?

Algebra ->  Conversion and Units of Measurement -> SOLUTION: I don't really know the topic. Which expression is equivalent to sin(2x) − sinx?       Log On


   

Question 1169138: I don't really know the topic.
Which expression is equivalent to sin(2x) − sinx?

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
sin%282x%29+%E2%88%92+sin%28x%29
since sin%282x%29=sin%28x%2Bx%29, use Angle-Sum Identity
sin%28alpha+%2B+beta%29+=+sin%28alpha%29+cos%28beta%29+%2B+cos%28alpha%29+sin%28beta%29 where alpha=x and beta=x
sin%28x+%2B+x%29+=+sin%28x%29+cos%28x%29+%2B+cos%28x%29+sin%28x%29=2sin%28x%29cos%28x%29
then you have
2sin%28x%29cos%28x%29-sin%28x%29......factor out common sin%28x%29
sin%28x%29%282cos%28x%29-1%29=>expression is equivalent to sin%282x%29-sin%28x%29