When using polarplot, why does the argument come before the modulus?

I thought the convention for polar coordinates was (r,theta), not (theta, r)?

Is there a reason for this, or was this question a waste of space?

Answer 1

[John D'Errico]

There is no officiially agreed convention, nor can there really be one. Don't expect the author to have used the same conventions that you personally like to use. Any "convention" like this is purely based on personal perference and who you learned it from. Someone from a different country or background can easily think differently, and they would be just as validly correct as you.

Should it be (r,theta) or (theta,r)? Make sure that you know which was used. Make sure that you know if the software uses radians or degrees for the angle.

When using ANY software, read the help. If you don't, then expect to get random results.

Answer 2

[Steven Lord]

The polarplot function is using the same convention as the older polar function, with theta as the first input argument and rho the second. I'm not completely certain why polar uses that ordering (that function was introduced before I joined MathWorks) but if I had to guess I'd guess it was for similarity to plot.

The plot function accepts x and y coordinates and plots (effectively) y = f(x).

The polar function accepts theta and rho coordinates and plots (effectively) rho = f(theta).

The polarplot function accepts theta and rho coordinates and plots (effectively) rho = f(theta).