# Trig problem

• September 18th 2008, 11:48 AM
john11235
Trig problem
I'm having a little trouble with this trig problem.

tan(a) = -(3/2) and sin(a) < 0. Evaluate the following:
sin(a)
cos(a)
sec(a)
csc(a)
cot(a)

I've already gotten that cot(a) = -(2/3) but I have no clue how to get any of the others.
• September 18th 2008, 11:53 AM
hwhelper
sec^2 a = tan^2 a + 1
sec a = 1 / cos a
Go from there.
• September 18th 2008, 11:58 AM
icemanfan
Draw a triangle with y = -3a and x = 2a, and then calculate the value for r (the hypotenuse) by using the Pythagorean Theorem: $x^2 + y^2 = r^2$. Since all basic trig functions are functions of some combination of x, y, and r, you should be able to calculate all of them once you know r.