How do you verify #cos^2 2A = (1+cos4A)/2#?

Question

8170 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-05-11T17:57:50

see below

Use Property:
#cos2A=2cos^2A-1#

Right Hand Side :#=(1+cos4A)/2#

#=(1+cos2(2A))/2#

#=(1+(2cos^2(2A)-1))/2#

#=(1-1+2cos^2(2A))/2#

#=(cancel1-cancel1+2cos^2(2A))/2#

#=(2cos^2(2A))/2#

#=(cancel2cos^2(2A))/cancel2#

#=cos^2(2A)#

#=# Left Hand Side