Graph of 1/x²
The graph of y = 1/x² looks like a volcano: two branches, both above the x-axis, shooting up on either side of the y-axis and flattening toward the x-axis far away.
Key features
- Domain
- x ≠ 0
- Range
- y > 0
- Vertical asymptote
- x = 0
- Horizontal asymptote
- y = 0
- Symmetry
- Even: symmetric about the y-axis
- Monotonic
- Increasing for x < 0, decreasing for x > 0
- y-intercept
- None: x = 0 is an asymptote
- Derivative
- −2x3
- Antiderivative
- −1x+C
Derivative and antiderivative from the calculator’s algebra system. Domain, range and asymptotes are stated for real x.
What the graph of 1/x² looks like
Squaring x makes the output positive on both sides, so both branches sit above the x-axis, mirror images of each other in the y-axis.
It falls off much faster than 1/x: at x = 10, 1/x is 0.1 but 1/x² is 0.01. This inverse-square shape is how gravity, light intensity and electric force weaken with distance.
Near zero it rises faster too, which is why the area under 1/x² from 1 to infinity is finite (exactly 1) while the area under 1/x is infinite.
Points of interest
Found numerically to about twelve digits in the window −5 ≤ x ≤ 5, then shown in exact form where one exists.
- x-intercepts (roots)
- None in this window
- Local maxima
- None in this window
- Local minima
- None in this window
- Inflection points
- None in this window
Table of values
A few points to plot, with exact values where they are simple.
| x | y = 1/x² |
|---|---|
| −2 | 1/4 |
| −1 | 1 |
| −1/2 | 4 |
| 1/2 | 4 |
| 1 | 1 |
| 2 | 1/4 |
| 3 | 1/9 |
How to graph 1/x² by hand
- 1Draw the asymptotes x = 0 and y = 0.
- 2Plot (1, 1), (2, ¼), (½, 4) and their mirror images (−1, 1), (−2, ¼), (−½, 4).
- 3Draw two branches above the x-axis, rising along the y-axis and flattening toward the x-axis.
Transformations
How the graph moves when you change the formula. The original is 1/x² in blue.
y = 1/(x - 1)^2Shifted right: the asymptote moves to x = 1.y = 1/x^2 - 1Shifted down 1: now crosses the x-axis at x = ±1.y = -1/x^2Reflected: both branches below the x-axis.
Where it shows up
- Newton’s law of gravitation and Coulomb’s law: force proportional to 1/r².
- Light and sound intensity falling off with the square of the distance from a point source.
Frequently asked questions
What is the range of 1/x²?
Is 1/x² even or odd?
What is the difference between the graphs of 1/x and 1/x²?
Related graphs
A hyperbola with asymptotes along both axes.
The basic parabola: vertex (0, 0), opens upward.
The bell curve: peak (0, 1), area √π.
Halves every step: (0, 1), (1, ½), (2, ¼), …
Defined for x > 0, through (1, 0) and (e, 1).
A V with its vertex at the origin, slopes ±1.
Change the window, add sliders for a, b, h and k, trace the curve with your keyboard, or overlay its derivative.