Question

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

Answer 1

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)`