TI-BASIC: Loops?

[Ender]

x86] link=topic=5660.msg66252#msg66252 date=1145737663]
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) = √(r²-x²)
f(r) = 0
f(x) = -√(r²-x²)
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.