The required value of value of cospheta = √2/3, here correct option is d) √2/3.
The given equation is a Trignomatric Equation,
cos2pheta+cos^2pheta = 1
These are the equation which contains trigonometric operators such as sin, cos.. etc.. In algebraic operation.
cos2pheta + cos^2pheta = 1
Now we know that,
[tex]cos2x[/tex] = [tex]cos^2x -1[/tex]
so, substituting cos2pheta = 2cos^2pheta - 1
2cos^2pheta-1 + cos^2peta = 1
3cos^2peta = 2
cos^2pheta = 2/3
cospheta = √2/3
Thus, the required value for the cospheta = √2/3.
Learn more about trigonometry equations here:
https://brainly.com/question/22624805
#SPJ1