trigonometric identities ; proving identities

by **moirchesteban** » Tue Feb 27, 2007 5:46 am

pls help me out with these topic

by **Math Tutor** » Tue Feb 27, 2007 2:12 pm

Here there is more about trigonometric identities
Trigonometric identities

What is your concrete question?

by **pins8** » Wed Sep 19, 2007 12:41 am

cos (cube) x sin(squared) x = 1/16 (2cosx – cos3x – cos5x)

by **pins8** » Wed Sep 19, 2007 2:09 am

Please help me to prove this identities:

cos (cube) x sin(squared) x = 1/16 (2cosx – cos3x – cos5x)

by **pins8** » Wed Sep 19, 2007 2:20 am

Please help me to prove on this identities:

cos^3xsin^2 x = 1/16 (2cosx – cos3x – cos5x)

by **yppetrov** » Thu Sep 20, 2007 1:51 am

use these formulas: cos³x = 4cos³x - 3cos x
sin³x = 3sinc - 4sin³x
sin2x = 2sin(x)cos(x)
cos(5x) = cos(2x + 3x) = cos2x.cos3x - sin2x.sin3x

by **yppetrov** » Thu Sep 20, 2007 2:29 pm

Did it help you?