Find the value of tangent of angle A, given cos2A = 4/5, and A terminates in quadrant 2

Answer 1

I am not going to do them all for you. Let's see you try.

Answer 2

I have the same equation, so I will try. The "cos2A" is throwing me off. Since it is in QII it will be <90 and >180. Since it is a COS the value of theta should be x/r?

x in QII is negative so x=(-4)
r = 5
y = 3

Almost hate to go further if I am off

since TAN(theta)=y/x
TAN(theta)= 3/(-4)

here is where the "cos2A" throws me and I cant find any examples. Is it as simple as 2(3/5)?

Appreciate any clarity.