Function Evaluator
Type a function and the values you want it at. Faster than a calculator, and
it never forgets to tell you when the function has no value somewhere.
f (x ) =
Any letter works as the variable — write -16t^2+32t+48 and the
table labels itself t .
undefined means the function has no value there — division by zero,
or a point outside its domain. That is a fact about the function, not a
failure of the arithmetic.
Function Evaluator
A calculator for one function at many values. Type the function, choose the
values, read the table.
The four ways to choose values
Approach Closes in on a number from both sides —
0.9, 0.99, 0.999 then 1.001, 1.01, 1.1 — with the number itself in the
middle. This is the shape a limit table wants, and typing it by hand is
exactly the drudgery worth skipping.
List Whatever values you name, separated by commas.
Range From, to, and a step — an evenly spaced grid.
One value A single evaluation.
Undefined is an answer
Where a function has no value, the table says undefined and keeps the
row. It is not skipped and not shown as an error, because in a limit table
that row is the whole point: x = 1, and the table exists to show what happens
near 1 anyway.
The variable follows the function
Write t . You never have to tell it which letter you meant.
On a phone
This page is built to be opened from a QR code and used instead of a
calculator. Everything is reachable one-handed and the table stays readable
at phone width.
Putting it in a slide or a link
?f=(x%5E2-1)%2F(x-1)&x=~1
?f=1%2Fx&x=10,100,1000
?f=x%5E2&x=0:2:0.25
The x parameter carries the values in every mode: a number, a
comma list, from:to:step, or ~a to approach
a . See docs/url-api.md.
Close