# Question #fce84

##### 1 Answer

Jun 8, 2016

#### Explanation:

Use the identity

#sin2xsinx=cosx" "=>" "2sinxcosx(sinx)=cosx#

#=>" "2sin^2xcosx=cosx#

Subtract

#2sin^2xcosx-cosx=0#

Factor

#cosx(2sin^2x-1)=0#

Set both of these terms equal to

#cosx=0#

This occurs at

The other term is

#2sin^2x-1=0#

#sin^2x=1/2#

#sinx=+-sqrt(1/2)=+-1/sqrt2=+-sqrt2/2#

Sine equals

Note that the mathematical way to express that