Question

Given: cos(theta) = 3/5 and theta is located in the fourth quadrant; find cos (theta)/2

Answer 1

Is the attached equation the same as replacing the a with (theta)?

Answer 2

If so, here is my work..
cos(theta)/2=+/- sqrt((1-cos(theta))/2)
...= +/- sqrt((1-(3/5))/2)
...= +/- sqrt((2/5)/2)
...= +/- sqrt(1/5)
...= sqrt1/sqrt5
...= 1/sqrt5
...=1*sqrt5/sqrt5*sqrt5
...=sqrt5/5
cos(theta/2)=sqrt5/5

Answer 3

So would that mean that in the first box I would put 1/5 and in the second box (under the radical) I would put a 5?