I'm given this problem: find all angles theta, 0 </= theta </= 2(pi) which satisfy:

tan (theta) = -4.

tan theta = sin/cos = y/x = -4/1 or 4/-1

so the triangle is in the second and fourth quadrant. adjacent side = 1, opposite = 4, hypotenuse = root 17.

From here I don't know how to continue. I'm not even sure if it's possible to find this angle without a calculator.

Anyone remember how this works? Thanks.