trig
posted by Ryan .
Given that tan B= 7/24 with B in quadrant III, find sin 2B, cos 2B, and tan 2B, using angle identities.

Did you recognize the 72425 rightangled triangle?
then sin B = 7/25
cos B = 24/25
sin 2B = 2sinBcosB = 2(7/25)(24/25) = 336/625
cos2B = cos^2B  sin^2B = 576/625 49/625 = 527/625
tan2B = sin2B/cos2B = (336/625)รท(527/625) = 336/527