Arcsine function
arcsin(x), sin-1(x), inverse sine function.
Arcsin definition
The arcsine of x is defined as the inverse sine function of x when -1≤x≤1.
When the sine of y is equal to x:
sin y = x
Then the arcsine of x is equal to the inverse sine function of x, which is equal to y:
arcsin x = sin-1 x = y
Example
arcsin 1 = sin-1 1 = π/2 rad = 90°
Graph of arcsin

Arcsin rules
| Rule name | Rule | 
|---|---|
| Sine of arcsine | sin( arcsin x ) = x | 
| Arcsine of sine | arcsin( sin x ) = x+2kπ, when k∈ℤ (k is integer) | 
| Arcsin of negative argument | arcsin(-x) = - arcsin x | 
| Complementary angles | arcsin x = π/2 - arccos x = 90° - arccos x | 
| Arcsin sum | arcsin α + arcsin(β) = arcsin( α√(1-β2) + β√(1-α2) ) | 
| Arcsin difference | arcsin α - arcsin(β) = arcsin( α√(1-β2) - β√(1-α2) ) | 
| Cosine of arcsine | |
| Tangent of arcsine | |
| Derivative of arcsine | ![]()  | 
									
| Indefinite integral of arcsine | 
Arcsin table
| x | arcsin(x)
											 (rad)  | 
										arcsin(x)
											 (°)  | 
									
|---|---|---|
| -1 | -π/2 | -90° | 
| -√3/2 | -π/3 | -60° | 
| -√2/2 | -π/4 | -45° | 
| -1/2 | -π/6 | -30° | 
| 0 | 0 | 0° | 
| 1/2 | π/6 | 30° | 
| √2/2 | π/4 | 45° | 
| √3/2 | π/3 | 60° | 
| 1 | π/2 | 90° | 
