Hi, today I was writing my Identities final test and got stuck on one question which I couldn't solve.
The question was: If sinB=-\frac{5}{13} find the exact value of tan2B.
I've got this far, correct me if I went wrong anywhere: tan2B=\frac{sin2B}{cos2B}=\frac{2sinBcosB}{2cos^2B-1}...