Rewrite sin3x with cos and sin. I just want to know how to apply the double angle formula with the 3.
sin 3x =
sin (2x + x) =
sin2xcosx + sinxcos2x =
2sinxcosxcosx + sinx (2cos^2x - 1) =
2sinxcos^2x + 2sinxcos^2x - sinx =
4sinxcos^2x - sinx
sinx ( 4cos^2x - 1 )
Note......other answers are possible....!!!
