How do you evaluate $csc [a r c cos (- \frac{4}{5})]$ $csc[arc cos(-4/5)]$ ?

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Answer 1 · 2016-08-03T15:01:41

$\frac{5}{3}$ $5/3$

Let $a = a r c cos (- \frac{4}{5}) \in Q 2$ $a = arc cos (-4/5) in Q2$ .

Then, #cos a = -4/5, sin a = sqrt(1-cos^2a)=3/5.

The given expression = csc a = 1/sin a=5/3#. .

How do you evaluate csc[arccos(−45)]csc[arc cos(-4/5)]?