How do solve how to solve cosx-2sin^2x=1?

1 Answer
maganbhai P.
Mar 15, 2018

#x=2kpi,kinZ#

Explanation:

Here,
#cosx-2sin^2x=1=>cosx-2(1-cos^2x)=1#
#cosx-2+2cos^2x=1=>2cos^2x+cosx-3=0#
#=>2cos^2x+3cosx-2cosx-3=0#
#=>cosx(2cosx+3)-1(2cosx+3)=0#
#=>(2cosx+3)(cosx-1)=0#
#=>cosx=-3/2!in[-1,1]or cosx=1in[-1,1]#
#:.cosx=1=>x=2kpi,kinZ#

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