+0

# Interesting Question

0
107
2

If

$$\frac{\sin^2 3A}{\sin^2 A} - \frac{\cos^2 3A}{\cos^2 A} = 2$$

then find $$\cos2A$$

Sep 1, 2020

#1
+22
0

Hmm, this is an interesting problem. I believe maybe the use of trig identities would help but I'm not sure.

I doubt solving for A is necessary. Most likely I think that cos2A would pop up somehow. Not sure how though

Does anyone know how to do this? I also would like to know.

Sep 1, 2020
#2
0

cos 2A = 12/13.

Sep 1, 2020