How do you use sinθ=13 to find tanθ?

1 Answer
Jan 8, 2017

±24

Explanation:

First find cos t.
cos2t=1sin2t
cos2t=119=89
cost=±223
tant=sintcost=±(13)(322)=±122=±24
Note about the signs of tan t.
On the unit circle:
sin t = 1/3 --> cos t either + or - , there for --> tan t either + or -
Check by calculator.
sint=13 --> t=1947 and t=18019.47=16053
tan 19.47 = 0.35 and tan 160.53 = - 0.35
±24=±1.4145=±0.35 OK