Algebra Examples

$π \cos (π)$

Step 1

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

$π (- \cos (0))$

Step 2

The exact value of $\cos (0)$ is $1$ .

$π (- 1 \cdot 1)$

Step 3

Multiply $- 1$ by $1$ .

$π \cdot - 1$

Step 4

Move $- 1$ to the left of $π$ .

$- 1 \cdot π$

Step 5

Rewrite $- 1 π$ as $- π$ .

$- π$

Step 6

The result can be shown in multiple forms.

Exact Form:

$- π$

Decimal Form:

$- 3.14159265 \dots$