Function Grapher
Online function grapher: up to three functions on one plot, zeros, intersection points and a table of values. Polynomials, fractions, roots, absolute value, logarithms, sine and tangent.
The online graphing calculator plots up to three functions at once on a chosen interval, marks the zeros, the y-intercepts and the intersection points of the graphs, and gives a table of values. It supports polynomials, fractions, roots, absolute value, powers, logarithms and trigonometric functions — with breaks and asymptotes, like for 1/x and tan x.
How to enter functions
| Input | Meaning |
|---|---|
| x^2, x^3, x^(1/3) | power |
| 2x, 3(x − 1), x sin x | multiplication (the * sign can be omitted) |
| 1/x, (x + 1)/(x − 2) | division, fraction |
| sqrt(x), √x, cbrt(x) | square and cube root |
| |x|, abs(x) | absolute value |
| sin x, cos x, tan x, cot x | trigonometric functions (argument in radians) |
| arcsin x, arccos x, arctan x | inverse trigonometric functions |
| ln x, log x, 2^x, e^x, exp(x) | logarithms (log is base 10) and exponential functions |
| pi, π, e | the constants π ≈ 3.14159 and e ≈ 2.71828 |
A function argument without brackets continues up to the next sign: sin 2x = sin(2x), while sin x · cos x is a product. When in doubt, use brackets.
Graphs of the basic functions
- Linear y = kx + b — a straight line; k is the slope, b is the y-intercept.
- Quadratic y = ax2 + bx + c — a parabola with the vertex at x = −b / (2a); it opens upward when a > 0.
- Inverse proportion y = k/x — a hyperbola with the asymptotes x = 0 and y = 0.
- Square root y = √x — half of a parabola, defined for x ≥ 0.
- Exponential y = ax and logarithmic y = loga x — the graphs are symmetric about the line y = x.
- Sine wave y = sin x repeats with period 2π, y = tan x — with period π and asymptotes x = π/2 + πk.
How intersection points are found
The zeros of a function are the solutions of f(x) = 0, the intersection points of two graphs are the solutions of f(x) = g(x). The calculator finds them numerically with an accuracy of 10−9 and shows an exact number when the root is an integer, a simple fraction or a multiple of π.
Example. y = x2 − 3x + 2 crosses the x-axis at x = 1 and x = 2, and the y-axis at (0, 2).
Graph transformations
| Function | How to get it from the graph of y = f(x) |
|---|---|
| y = f(x) + b | shift up by b (down if b < 0) |
| y = f(x − a) | shift right by a (left if a < 0) |
| y = k · f(x) | vertical stretch by a factor of k |
| y = −f(x) | reflection in the x-axis |
| y = f(−x) | reflection in the y-axis |
| y = |f(x)| | the part below the x-axis is reflected upward |
Plot y = x2, y = (x − 2)2 and y = x2 + 1 together — the shifts are visible at once.
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