Given cos A = and that angle A is in Quadrant II, find the exact value ofAcsc A in simplest radical form using a rational denominator.89

Given Cos A And That Angle A Is In Quadrant II Find The Exact Value OfAcsc A In Simplest Radical Form Using A Rational Denominator89 class=

Answer :

cscA is the inverse of the sine of A.

[tex]cscA=(\sin A)^{-1}[/tex]

Since we know the value for the cosine, using the identity

[tex]\sin ^2A+\cos ^2A=1[/tex]

We can calculate the value for the sine.

[tex]\begin{gathered} (-\frac{8}{\sqrt[\square]{89}})^2+\sin ^2A=1 \\ \frac{64}{89}+\sin ^2A=1 \\ \sin ^2A=1-\frac{64}{89} \\ \sin A=\pm\sqrt[]{\frac{25}{89}} \\ \sin A=\pm\frac{5}{\sqrt[]{89}} \end{gathered}[/tex]

Since we know that the angle A is located at the Quadrant II, we know its sine is positive, then

[tex]\sin A=\frac{5}{\sqrt[]{89}}[/tex]

Now, using our first relation

[tex]\csc A=(\frac{5}{\sqrt[]{89}})^{-1}=\frac{\sqrt[]{89}}{5}[/tex]

And this is our final answer.