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acos()

Calculates the arc cosine of a number.

acos() is the inverse of cos(). It expects arguments in the range -1 to 1. By default, acos() returns values in the range 0 to π (about 3.14). If the angleMode() is DEGREES, then values are returned in the range 0 to 180.

Examples

acos example 1

function setup()
  size(100, 100)
  fill(0)

  background(200)

  -- Calculate cos() and acos() values.
  local a = PI
  local c = cos(a)
  local ac = acos(c)

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

  describe('The numbers 3.142, -1, and 3.142 written on separate rows.')
end

acos example 2

function setup() 
  size(100, 100)

  background(200)
  fill(0)

  -- Calculate cos() and acos() values.
  local a = PI + QUARTER_PI
  local c = cos(a)
  local ac = acos(c)

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

  describe('The numbers 3.927, -0.707, and 2.356 written on separate rows.')
end

Syntax

acos(value)

Parameters

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

Returns

Number: arc cosine of the given value.