Trigonometry Examples

$y = \sin (270 °)$

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.

$y = - \sin (90)$

Step 2

The exact value of $\sin (90)$ is $1$ .

$y = - 1 \cdot 1$

Step 3

Multiply $- 1$ by $1$ .

$y = - 1$