Posted by Hello on .
what is the derivative of:
y=2sinxcosx

Calculus 
Reiny,
to ways to do it
1. recognize that 2sinxcosx = sin(2x)
then dy/dx = 2cos(2x)
or
2. y = 2sinxcosx
dy/dx = 2sinx(sinx) + 2cosx(cosx)
= 2(cos^2x  sin^2x)
which just happens to be 2cos(2x) as above