Chapter 4.2, Problem 34E

Solution

To calculate the given trigonometric function using calculator.

  $\sin \left(\frac{\pi }{15}\right)\approx \text{0}\text{.20}8$

Given information:

  $\sin \left(\frac{\pi }{15}\right)$ .

Formula used:

• The trigonometric function of an angle $\theta$ of a right angled triangle $\Delta ABC$ are:

    $\sin \theta =\frac{opp}{hyp}$

Where opp is the opposite side to the angle $\theta$ , adj is the adjacent side to the angle $\theta$ , and hyp is the hypotenuse of the triangle.

Calculation:

In order to find the value of the trigonometric function

  $\sin \left(\frac{\pi }{15}\right)$ using calculator, first make sure note that the calculator is in radian mode since the angle given is in radian, if it is not then change it into radian mode.

Now type on calculator first press the trigonometric function “sin” button, then click on parenthesis () and the type $\pi ÷15$ inside it, and click “=” sign.

It will give the answer

  $\sin \left(\frac{\pi }{15}\right)\approx \text{0}\text{.20}8$