Q17. - Algebra 2

Question

Find the values of six trigonometric functions for angle  shown below.

Step-by-Step Solution

Answer

The six trigonometric functions are: $\sin \theta =\frac{\sqrt{7}}{4},\csc \theta =\frac{4}{\sqrt{7}},\cos \theta =\frac{3}{4},\sec \theta =\frac{4}{3},\tan \theta =\frac{\sqrt{7}}{3},\cot \theta =\frac{3}{\sqrt{7}}$.

Step 1. Write down the given information.

The given figure is shown below.

Step 2. Concept used.

The six trigonometric functions are $\sin \theta , \csc \theta , \cos \theta , \sec \theta , \tan \theta , \cot \theta$.  

Let $(x,y)$ be a point in X-Y plane and (r) be the length of a line segment drawn from the origin to the point.

In, $\Delta OAB,OA=r, OB=x, AB=y$

Therefore, six trigonometric functions are;

$\begin{array}{c}\sin \theta =\frac{AB}{OA}=\frac{y}{r},\csc \theta =\frac{1}{\sin \theta }=\frac{OA}{AB}=\frac{r}{y}\\ \cos \theta =\frac{OB}{OA}=\frac{x}{r},\sec \theta =\frac{1}{\cos \theta }=\frac{OA}{OB}=\frac{r}{x}\\ \tan \theta =\frac{AB}{OB}=\frac{y}{x},\cot \theta =\frac{1}{\tan \theta }=\frac{OB}{AB}=\frac{x}{y}\end{array}$           

Step 3. Calculation.

From the given figure, the side opposite to angle $\left(\theta \right)$ is evaluated as:

$\begin{array}{c}\text{Opposite}=\sqrt{{16}^2-{12}^2}\\ =4\sqrt{7}\end{array}$

Now, the six trigonometric functions are evaluated as:

$\begin{array}{c}\sin \theta =\frac{4\sqrt{7}}{16}=\frac{\sqrt{7}}{4}\csc \theta =\frac{4}{\sqrt{7}}\\ \cos \theta =\frac{12}{16}=\frac{3}{4}\sec \theta =\frac{4}{3}\\ \tan \theta =\frac{\sqrt{7}}{3}\cot \theta =\frac{3}{\sqrt{7}}\end{array}$

Step 4. Conclusion.

The six trigonometric functions are: $\sin \theta =\frac{\sqrt{7}}{4},\csc \theta =\frac{4}{\sqrt{7}},\cos \theta =\frac{3}{4},\sec \theta =\frac{4}{3},\tan \theta =\frac{\sqrt{7}}{3},\cot \theta =\frac{3}{\sqrt{7}}$