Hello, can someone please help me solve this problem? How do you solve: Cos2theta + 2Cos^2theta=0 ?

Question

268 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-03-14T16:41:03

#rarrx=2npi+-pi#

#rarrx=2npi+-(pi/2)# #nrarrZZ#

#rarrcos2x+cos^2x=0#

#rarr2cos^2x-1-cos^2x=0#

#rarrcos^2x-1=0#

#rarrcosx=+-1#

when #cosx=1#

#rarrcosx=cos(pi/2)#

#rarrx=2npi+-(pi/2)#

When #cosx=-1#

#rarrcosx=cospi#

#rarrx=2npi+-pi#