Thread: Trigonometric Problem

Hi there,
Can anyone give me help to start off this problem please?

Triangle PQR Angle PRQ = 3x; Angle PQR = x

I have to prove that p = 4q cos x cos 2x.

Thanks
Cromlix

Originally Posted by cromlix

Hi there,
Can anyone give me help to start off this problem please?

Triangle PQR Angle PRQ = 3x; Angle PQR = x

I have to prove that p = 4q cos x cos 2x.

Thanks
Cromlix

law of sines ...





... taking it from this point will lead to what you want proved