Graph of arcsin x (inverse sine)
The inverse sine graph undoes sine on the interval −π/2 ≤ y ≤ π/2. It runs from (−1, −π/2) to (1, π/2) through the origin, and it is the sine graph reflected in the line y = x.
Key features
- Domain
- −1 ≤ x ≤ 1
- Range
- −π/2 ≤ y ≤ π/2
- End points
- (−1, −π/2) and (1, π/2)
- Monotonic
- Increasing on its whole domain
- Vertical tangents
- At x = ±1, where the slope 1/√(1 − x²) is infinite
- Symmetry
- Odd: arcsin(−x) = −arcsin x
- y-intercept
- None
- Derivative
- 1√1−x2
- Antiderivative
- xarcsin(x)+√1−x2+C
Derivative and antiderivative from the calculator’s algebra system. Domain, range and asymptotes are stated for real x.
What the graph of arcsin x looks like
Sine is not one-to-one, so it has no inverse on its whole domain. Restricting it to −π/2 ≤ x ≤ π/2, where it rises from −1 to 1 exactly once, makes it invertible, and arcsin is the inverse of that piece.
Reflecting that piece of the sine curve in the line y = x gives the arcsin graph: a short S-shape that is almost straight near the origin (arcsin x ≈ x for small x) and becomes vertical at its two ends.
The graph only exists for −1 ≤ x ≤ 1, because sine never produces values outside that interval. Asking for arcsin 2 has no real answer.
Points of interest
Found numerically to about twelve digits in the window −3 ≤ x ≤ 3, then shown in exact form where one exists.
- x-intercepts (roots)
- x = 0
- Local maxima
- None in this window
- Local minima
- None in this window
- Inflection points
- (0, 0)
Table of values
A few points to plot, with exact values where they are simple.
| x | y = arcsin x |
|---|---|
| −1 | −π/2 |
| −√3/2 | −π/3 |
| −1/2 | −π/6 |
| 0 | 0 |
| 1/2 | π/6 |
| √2/2 | π/4 |
| 1 | π/2 |
How to graph arcsin x by hand
- 1Mark the end points (−1, −π/2) and (1, π/2), with π/2 ≈ 1.57, and the origin.
- 2Add (1/2, π/6) and (−1/2, −π/6), with π/6 ≈ 0.52.
- 3Join them with an S-curve that is nearly straight through the origin and turns vertical at both end points.
Transformations
How the graph moves when you change the formula. The original is arcsin x in blue.
y = asin(x/2)Domain widened to −2 ≤ x ≤ 2.y = 2asin(x)Range stretched to −π ≤ y ≤ π.y = asin(x) + pi/2Shifted up π/2, so it runs from 0 to π. This equals π − arccos x.
Frequently asked questions
What is the domain of arcsin x?
What is the range of arcsin x?
Is arcsin x the same as 1/sin x?
What is the derivative of arcsin x?
Related graphs
Period 2π, amplitude 1, zeros at every multiple of π.
Domain [−1, 1], range [0, π], always decreasing.
All real inputs, outputs between −π/2 and π/2.
The sine wave shifted left by π/2; starts at its peak.
Starts at the origin; half of a sideways parabola.
1/sin x: asymptotes at every multiple of π.
Change the window, add sliders for a, b, h and k, trace the curve with your keyboard, or overlay its derivative.