You know, on TI graphing calculators, to draw a circle, it's just two graphed equations:
y1=sqrt(r2 - x2)
y2=-sqrt(r2 - x2)
where r is the radius of the circle you would like drawn. This is derived from the definition equation of a circle, x2 + y2 = r2.
I'm pretty sure in the past, for me, something like If A < 100 Then Goto B worked.
I believe that will draw only a partial circle, as seperating the equation into two restricts the domain.
f(x) = √(r
2-x
2)
f(r) = 0
f(x) = -√(r
2-x
2)
f(-r) = 0
Those are two points missing from your graph. The domains, as defined by the square root function, do not restrict x = ±r. As Myndfyre said, it is the granularity of your calculator that is causing the perceived discontinuities. But by setting your window to x: [-r, r] and y: [-r, r], and setting r to small values, you should be able to see a clearly defined circle.
