How do you verify cos^2 2A = (1+cos4A)/2cos22A=1+cos4A2?

1 Answer
May 11, 2016

see below

Explanation:

Use Property:
cos2A=2cos^2A-1cos2A=2cos2A1

Right Hand Side :=(1+cos4A)/2=1+cos4A2

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

=(1+(2cos^2(2A)-1))/2=1+(2cos2(2A)1)2

=(1-1+2cos^2(2A))/2=11+2cos2(2A)2

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

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

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

=cos^2(2A)

= Left Hand Side