Question

what is the derivative of cosxsin3x?

Answer 1

\[(-sinx)(\sin3x)+cosx(\cos3x)(3)\]
\[-\sin^23x+3\cos^23x\]

Answer 2

@winterfez you can't combing the sines and cosines like that

Answer 3

*combine

Answer 4

is cosx time sin3x, thus I can use addition for derivative

Answer 5

\[(-\sin(x))\sin(3x)\ne -\sin^2(3x)\]

Answer 6

oh that was what you were pointing out..THANKS..didnt see that mistake