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May 29, 2016
Posted by **Hello** on Friday, March 11, 2011 at 10:32am.

y=2sinxcosx

- Calculus -
**Reiny**, Friday, March 11, 2011 at 10:42amto 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