Question

If cos theta = 1, then the value of cos 2theta is

(a) 7/9 b)-5/10 c) -7/9 d) 5/10​

Answer 1

Step-by-step explanation:

cos 2theta =2cos^2theta -1

=2(1)^2-1

=2-1

=1

Answer 2

cosθ = 1

Then θ = 90

then cos 180 = -1

       Then the value is -1

Please check the options Your options are wrong

Mark the brainliest plz plz