Chapter 4.3, Problem 37E

(a)

To determine

To find: The value of given function using the calculator.

Answer to Problem 37E

The value of $\cot 11°15\text{'}=\cot 11.25°$ , to four places is $5\cdot 0273$ .

Explanation of Solution

Given information:

The given function is $\cot 11°15\text{'}$ .

Calculation:

Convert the angle to decimal degree using the following relation.

  $1\text{'}=\left(\frac{1}{60}\right)°$ and $1\text{'}\text{'}=\left(\frac{1}{3600}\right)°$

Calculate the value of $11°15\text{'}$ .

  $\begin{array}{c}11°15\text{'}=11°+\left(\frac{15}{60}\right)°\\ =11\cdot 25°\end{array}$

Now the angle is in degree.

Set the mode of the calculator to degree mode.

As we know that cotangent is the reciprocal function of the tangent function.

The calculator keystrokes as follows.

  $\boxed{(}\boxed{\text{TAN}}\boxed{(}11\cdot 25\boxed{)}\boxed{)}\boxed{x^{-1}}\boxed{\text{ENTER}}$

The answer displayed on the calculator is $5\cdot 0273$ .

Therefore, the value of $\cot 11°15\text{'}=\cot 11.25°$ ,to four places is $5\cdot 0273$ .

(b)

To determine

To find: The value of given function using the calculator.

Answer to Problem 37E

The value of $\tan 11°15\text{'}=\tan 11.25°$ , to four places is $0\cdot 1989$ .

Explanation of Solution

Given information:

The given function is $\tan 11°15\text{'}$ .

Calculation:

Convert the angle to decimal degree using the following relation.

  $1\text{'}=\left(\frac{1}{60}\right)°$ and $1\text{'}\text{'}=\left(\frac{1}{3600}\right)°$

Calculate the value of $11°15\text{'}$ .

  $\begin{array}{c}11°15\text{'}=11°+\left(\frac{15}{60}\right)°\\ =11\cdot 25°\end{array}$

Now, the angle is in degree.

Set the mode of the calculator to degree mode.

The calculator keystrokes as follows.

  $\boxed{\text{TAN}}\boxed{(}11\cdot 25\boxed{)}\boxed{\text{ENTER}}$

The answer displayed on the calculator is $0\cdot 1989$ .

Therefore, the value of $\tan 11°15\text{'}=\tan 11.25°$ , to four places is $0\cdot 1989$ .