How do you graph r=θ?

1 Answer
Feb 28, 2018

The graph is a spiral that starts from the origin of coordinates (when θ=0) and unravels counterclockwise.

Explanation:

As θ increases from 0 to π/2, the graph moves from the the origin of coordinates counterclockwise, getting farther and farther from it.

It intercepts the Y-axis at point π/2 because, when θ=π/2, r=π/2.
Therefore, x=rcos(θ)=(π/2)cos(π/2)=0 and y=rsin(θ)=(π/2)sin(π/2)=π/2.

Similarly, as θ increase to π, the graph intercepts X-axis at π.

Then Y-axis at 3π/2.
Then X-axis at 2π etc.

That's how a spiral form is made.

Do a Google search for "r=theta graph" to see how the graph looks.