Question

2 cos2ø=1 find ø show that​

Answer 1

Solution:

Given 2cos2ø=1

=> cos2ø=1/2

=> cos2ø=cos 60°

=> 2ø=60

=> ø=60/2

=> ø=30°

Therefore ,

ø=30°

••••

Answer 2

2 Cos2\theta = 1

=2(2Cos^2\theta-1) = 1

=4Cos^2\theta-2 = 1

=4Cos^2\theta = 1-2

=4Cos^2\theta = -1

=Cos^2\theta = -1/4

=Cos\theta = \sqrt{-1/4}

=Cos\theta = -1/2

=Cos\theta = Cos240

=\theta=240