Not all angles come from triangles.{{CMD_55}} Given a right triangle like {{CMD_56}} {{ENV_57}} {{CMD_58}} the angle {{MATH_59}} cannot be negative and cannot exceed {{MATH_60}} radians. That means to talk about trigonometric functions for {{CMD_61}}other{{CMD_62}} angles, we need to be able to describe the trigonometric functions a little more generally. To do this, we use the unit circle from the previous section. Given an angle {{MATH_63}}, we construct the angle with initial side along the positive {{MATH_64}}-axis and vertex at the origin.