Chapter 13.2, Problem 4WE

To determine

To complete: the table.

Answer to Problem 4WE

The function are $\sin 1.4=0.9854,\cos 1.4=0.1700,\tan 1.4=5.7979$ .

Explanation of Solution

Given table:

  $8.$   $9.$   $10.$   $11.$   $12.$   $13.$

	$\sin s$	$\cos s$	$\tan s$	$\cot s$	$\sec s$	$\csc s$
$0<s<\frac{\pi }{2}$	$?$	$?$	$?$	$?$	$?$	$?$
$\frac{\pi }{2}<s<\pi$	$?$	$?$	$?$	$?$	$?$	$?$
$\pi <s<\frac{3\pi }{2}$	$?$	$?$	$?$	$?$	$?$	$?$
$\frac{3\pi }{2}<s<2\pi$	$?$	$?$	$?$	$?$	$?$	$?$

Find the sine, cosine and tangent if the number $1.4$ to four decimal places.

By using calculator and setting the calculator in radian mode.

  $\begin{array}{c}\sin 1.4=0.98544973\\ =0.9854\\ \cos 1.4=0.1699671429\\ =0.1700\\ \tan 1.4=5.797883715\\ =5.7979\end{array}$

Calculation:

Let use a calculator to find the value.

Set the calculator in radian mode. We have to find the sine of the given number.

Press the key $\boxed{\sin }$ , and enter the number $0.25$ . The display will be $0.24740396$ .

Approximate the value to four decimal places.

  $0.24740396=0.2474$

To find the cosine of $0.25$ .

Press the key $\boxed{\cos }$ , and enter the number $0.25$ . The display will be $0.96891242$ .

Approximate the value to four decimal places.

  $0.96891242=0.9690$

Similarly, find the tangent of $0.25$ .

  $\begin{array}{c}\tan 0.25=0.25534192\\ =0.2553\end{array}$

Therefore, we found the sine, cosine, and tangent of the given number.