CPM Homework Help : CCA2 Problem 7-110

Compute without a calculator For angle $θ$ in the third quadrant, $\cosθ=−\frac{12}{13}$ . Use this information to find each of the following values without using calculator.

Hint:

Draw a unit circle and label the triangle for the given angle. Unit Circle, with right triangle, hypotenuse from center, to a point, in third quadrant, on the circle, vertical leg, from point on circle, perpendicular to negative, x axis, horizontal leg, labeled negative 12 thirteenths, is a portion of negative, x axis.

More Help:

Find the missing side of the triangle using the Pythagorean Theorem.
Use the missing side to evaluate the given trig ratios.
Remember that both $x\text{ and}\ y$ are negative in the third quadrant.

$\sin θ$

$\tan θ$
Answer (b):
$\tan\theta=\frac{5}{12}$