Precalculus Examples

$\cot (\arccos (- \frac{15}{17}))$

Step 1

Draw a triangle in the plane with vertices $(- \frac{15}{17}, \sqrt{1^{2} - {(- \frac{15}{17})}^{2}})$ , $(- \frac{15}{17}, 0)$ , and the origin. Then $\arccos (- \frac{15}{17})$ is the angle between the positive x-axis and the ray beginning at the origin and passing through $(- \frac{15}{17}, \sqrt{1^{2} - {(- \frac{15}{17})}^{2}})$ . Therefore, $\cot (\arccos (- \frac{15}{17}))$ is $- \frac{15}{8}$ .

$- \frac{15}{8}$

Step 2

The result can be shown in multiple forms.

Exact Form:

$- \frac{15}{8}$

Decimal Form:

$- 1.875$

Mixed Number Form:

$- 1 \frac{7}{8}$