Algebra Examples

$\sec (- 840 °)$

Step 1

Add full rotations of $360$ ° until the angle is between $0$ ° and $360$ °.

$\sec (240)$

Step 2

Apply the reference angle by finding the angle with equivalent trig values in the first quadrant. Make the expression negative because secant is negative in the third quadrant.

$- \sec (60)$

Step 3

The exact value of $\sec (60)$ is $2$ .

$- 1 \cdot 2$

Step 4

Multiply $- 1$ by $2$ .

$- 2$