Type an expression in terms of x and it's plotted immediately — no y= needed, though
it's accepted and stripped if you type it. The parser is a small hand-written recursive-descent evaluator
(no eval involved), so 2x, 2*x and x*2 all mean exactly
the same thing, and unsupported input is rejected rather than silently misread.
Plotting 1/x shows two separate branches meeting nowhere near x = 0 — because division by zero is undefined, not infinite in a drawable sense, the curve correctly breaks into two pieces instead of joining with a vertical line.
Standard notation: +, -, *, /, ^ for powers, and parentheses. sin, cos, tan, asin, acos, atan, sqrt, cbrt, abs, ln, log, log2, exp, floor, ceil, round and sign all work, along with the constants pi and e. Implicit multiplication works too — 2x, 2sin(x) and (x+1)(x-1) are all understood without a * sign.
A vertical line at an asymptote like x=0 for 1/x isn't actually part of the function's graph — the function is undefined there, not infinite in a way that draws a line. This tool detects the jump and breaks the curve into separate pieces, the same way a correct hand-drawn sketch would.
Yes — the x and y axes always share the same scale (the same number of pixels per unit), so a function like sqrt(9-x^2) traces a genuine semicircle rather than a squashed ellipse, at every zoom level.
Up to eight, each in its own colour, any of which can be hidden or deleted independently — useful for comparing a function against its derivative, or seeing where two curves intersect.