Algebra Examples

$\arctan (\cos (π))$

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.

$\arctan (- \cos (0))$

Step 2

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

$\arctan (- 1 \cdot 1)$

Step 3

Multiply $- 1$ by $1$ .

$\arctan (- 1)$

Step 4

The exact value of $\arctan (- 1)$ is $- \frac{π}{4}$ .

$- \frac{π}{4}$

Step 5

The result can be shown in multiple forms.

Exact Form:

$- \frac{π}{4}$

Decimal Form:

$- 0.78539816 \dots$