How do you simplify $cosx(2sinx + cosx)-sin^2x$ ?

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Answer 1 · 2015-02-16T18:38:05

You can start by multiplying $cos(x)$ to get:

$2sin(x)cos(x)+cos^2(x)-sin^2(x)=$ or:

$=[2sin(x)cos(x)]+[cos^2(x)-sin^2(x)]=$

which can be written as:

$=sin(2x)+cos(2x)$

How do you simplify cosx(2sinx + cosx)-sin^2xcosx(2sinx + cosx)-sin^2x?