Question

Diffrentiate sinxcos3x. Please explain the solution. ​

Answer 1

Answer:

$= >$

y = sinxcos3x

we know ,

if, y=uv

then,

dy/dx=[ u. dv/dx+v.du/dx]

therefor

y=sinxcos3x

dy/dx=sinx.d/dx(cos3x)

+cos3x.d/dx(sinx)

= sinx. (-sin3x. 3)

+cos3x. cosx

= -3sin^2 3x+cos^2 3x

final answer is -3sin^2 3X +cos^2 3x