Find the exact value of $\cos\left(\frac{5\pi}{6}\right)$ using the 3 step process discussed in the lecture notes.
1.) The reference angle is
(Type your answer in radians. Type an exact answer, using $\pi$ as needed.)
2.) Apply the trig function to the reference angle: $\cos\left(\boxed{\qquad}\right)=\boxed{\qquad}$
3.) Apply the appropriate sign: $\cos\left(\frac{5\pi}{6}\right)=\boxed{\qquad}$
(Type an exact answer, using radicals as needed. Use integers or fractions for any numbers in the expression.)
