Trigonometry Examples

sin (- 135 °)

$\sin (- 135 °)$

Step 1

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

$- \sin (45)$

Step 2

The exact value of

$\sin (45)$ is

$\frac{\sqrt{2}}{2}$ .

$- \frac{\sqrt{2}}{2}$

Step 3

The result can be shown in multiple forms.

Exact Form:

$- \frac{\sqrt{2}}{2}$

Decimal Form:

$- 0.70710678 \dots$