Posted by chama on Wednesday, March 14, 2012 at 11:02am.
Prove that sin3theta=3sintheta4sin^3theta

maths  Reiny, Wednesday, March 14, 2012 at 11:08am
prove sin (3Ø) = 3sin Ø  4sin^3 Ø
LS = sin(2Ø + Ø)
= sin2Ø cosØ + cos2ØsinØ
= 2sinØcosØcosØ + (12sin^2 Ø)sinØ
= 2sinØ(1sin^2 Ø) + sinØ  2sin^3 Ø
= 2sinØ  2sin^2 Ø + sinØ  2sin^3 Ø
= 3sinØ  4sin^2 Ø
= RS