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asin()

Calculates the arc sine of a number.

asin() is the inverse of sin(). It expects input values in the range of -1 to 1. By default, asin() returns values in the range -π ÷ 2 (about -1.57) to π ÷ 2 (about 1.57). If the angleMode() is DEGREES then values are returned in the range -90 to 90.

Examples

asin example 1

function setup()
  size(100, 100)

  background(200)
  fill(0)

  -- Calculate sin() and asin() values.
  local a = PI / 3
  local s = sin(a)
  local as = asin(s)

  -- Display the values.
  text(round(a, 3), 35, 25)
  text(round(s, 3), 35, 50)
  text(round(as, 3), 35, 75)

  describe('The numbers 1.047, 0.866, and 1.047 written on separate rows.')
end

asin example 2

function setup()
  size(100, 100)

  fill(0)
  background(200)

  -- Calculate sin() and asin() values.
  local a = PI + PI / 3
  local s = sin(a)
  local as = asin(s)

  -- Display the values.
  text(round(a, 3), 35, 25)
  text(round(s, 3), 35, 50)
  text(round(as, 3), 35, 75)

  describe('The numbers 4.189, -0.866, and -1.047 written on separate rows.')
end

Syntax

asin(value)

Parameters

Parameter
value Number: value whose arc sine is to be returned

Returns

Number: arc sine of the given value

This reference page contains content adapted from p5.js and Processing by p5.js Contributors and Processing Foundation, licensed under CC BY-NC-SA 4.0.