Find the exact value of each of the remaining trigonometric functions of $\theta$. Rationalize denominators when applicable. $\sec \theta=-9$, given that $\sin \theta> 0$
Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. $\sin \theta=$ (Simplify your answer, including any radicals. Use integers or fractions for any numbers in the expression.)
B. The function is undefined.
So, the exact value of $\sin \theta$ is $\boxed{\frac{4\sqrt{5}}{9}}$.
Step 1 :Given that $\sec \theta = -9$, we can rewrite this as $\cos \theta = -\frac{1}{9}$.
Step 2 :Since $\sin^2 \theta + \cos^2 \theta = 1$, we can substitute $\cos \theta$ into this equation to find $\sin \theta$.
Step 3 :Substituting $\cos \theta = -\frac{1}{9}$ into the equation, we get $\sin^2 \theta + \left(-\frac{1}{9}\right)^2 = 1$.
Step 4 :Solving this equation, we get $\sin^2 \theta = 1 - \left(-\frac{1}{9}\right)^2 = 1 - \frac{1}{81} = \frac{80}{81}$.
Step 5 :Taking the square root of both sides, we get $\sin \theta = \pm \sqrt{\frac{80}{81}}$.
Step 6 :However, we are given that $\sin \theta > 0$, so $\sin \theta = \sqrt{\frac{80}{81}}$.
Step 7 :Rationalizing the denominator, we get $\sin \theta = \frac{\sqrt{80}}{9}$.
Step 8 :Finally, simplifying the radical, we get $\sin \theta = \frac{4\sqrt{5}}{9}$.
Step 9 :So, the exact value of $\sin \theta$ is $\boxed{\frac{4\sqrt{5}}{9}}$.