I was wondering how graphing calculators were able to plot functions and relations so quickly.
For a funtion, I can see just testing all the x values numerically in a domain, and outputting it that way. But how does this work for relations (such as x^2 + y^2 = 1)? Numerically testing every possible x and y value isn't that fast, as it would be O(n^2), right? How is it possible?
Thank you.