Chapter 6, Problem 14CT

To determine

The value of the expression, $\cos \frac{2\pi }{5}$ rounded to three decimal places using a calculator.

Answer to Problem 14CT

Solution:

The value of the expression $\cos \frac{2\pi }{5}$ is approximately $0.309$ .

Explanation of Solution

Given information:

The expression, $\cos \frac{2\pi }{5}$ .

Let, the expression be $\cos \frac{2\pi }{5}$ .

To find the value of the expression using calculator first set the mode of calculator to receive radians.

By using calculator, $\cos \frac{2\pi }{5}=0.3090169944$

Rounding to three decimal places gives, $\cos \frac{2\pi }{5}\approx 0.309$ .

Hence, the value of the expression $\cos \frac{2\pi }{5}$ is approximately, $0.309$ .