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Trigonometry reference

Arcsine function

arcsin(x), inverse sine 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

diagram

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° |