Chapter EP, Problem 13.6.8EP

To determine

To Find: The value of the given function.

Answer to Problem 13.6.8EP

The value of the function is $-\frac{1}{\sqrt{2}}$ .

Explanation of Solution

Given:

The given function is $\cos \left(2295°\right)$ .

Calculation:

Consider the given function is,

$\cos \left(\frac{3\pi }{4}\right)$

This shows that the angle is in the second quadrant and the cosine function is negative in the third quadrant then,

$\begin{array}{c}\cos \left(2295°\right)=\cos \left(2160°+135°\right)\\ =\cos \left(135°\right)\\ =\cos \left(90°+45°\right)\\ =-\sin 45°\end{array}$

Then,

$-\sin 45°=-\frac{1}{\sqrt{2}}$

Thus, the value of the function is $-\frac{1}{\sqrt{2}}$ .