Question

How do you graph `theta=-840^circ`?

Answer 1

graph{-tan(2pi/3)x [-10, 10, -5, 5]}

Explanation:

First you simplify the angle so it's between 0 and 360º

`-840º = -360º - 480º = -360º - 360º - 120º`

So we have the equation

`theta = -120º`

That means it's 120 degrees clockwise from the `x^+` semiaxis (because of the sign), or in another way, 240 degrees counter-clockwise from the `x^+` semiaxis.

Since we only have an angle, the radius can be any real value, so our equation describes a line. Just find the appropriate angle on the graph paper and trace a line through it.

Or, if you only have rectangular graph paper / no protactor nearby, calculate the rate of growth of the line (`tan(-120)`) and take two points within that line to trace it.