Recall that sin(2x) = 2sinxcosx
Proof of sin(2x):
[tex]sin(2x) = sin(x + x)[/tex]
Using the Addition property:
[tex]sin(x + x) = sin(x) cos(x) + cos(x) sin(x) = 2sinxcosx[/tex]
[tex]\therefore sin(2x) + sin(x) = 2sin(x)cos(x) + sin(x)[/tex]
[tex]= sin(x)[2cos(x) + 1][/tex]
