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

1 Answer
Mar 8, 2017

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


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.