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I don't understand your question. You want an angle in quadrant 3 but 78.99 is in quadrant 1, and secant (-5.2408) = 1.953490535...
If your calculator does not have sec, you can invert things and work with the cos.
It only has sin cos tan yes
i did cos^-1(5.2408) and got 79 but that cant be the angle because its not between 180 and 270
Yah, use the identity \(\dfrac {1}{\sin\theta}= \sec\theta\)
Oops. I meant cos there. LOL
\(\dfrac {1}{\cos\theta}= \sec\theta \implies \dfrac {1}{\cos\theta}=-5.2408\implies \) \(\cos\theta=\dfrac {1}{-5.2408}\)
So what is \(\cos^{-1}\left(\dfrac {1}{-5.2408}\right)\)
101
but that's not between 180 and 270 either
Ah, but this is cosine. An x vlaue. What other angle is in the proper quad, but with the right x vlaue?
sin..
No, no... by x value. |dw:1381559709285:dw|
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