Cos Inverse Calculator (Arccos)

Your details

Any real number from -1 to 1 inclusive. Values outside this domain have no real arccos.
Choose which unit headlines the result. The steps panel always shows degrees, radians and pi-radians.
Angle (degrees)Acute angle
60deg

Principal angle in degrees, always in the range 0 to 180

Angle (pi-radians)0.333333pi rad
Exact symbolic formpi/3
Complementary angle30deg
60 deg
Acute (small)<45Acute45-90Right90-91Obtuse91-135Obtuse (large)135+

arccos(0.5) = 60.0000 deg

  • cos(60.0000 deg) = 0.5, which confirms the inverse: arccos(0.5) = 60.0000 deg.
  • In radians this is 1.047198 rad, or 0.333333 * pi.
  • This is a unit-circle value with exact form: pi/3.

Next stepTo verify, take cos(60.0000 deg) and you should get back 0.500000. For the complementary function, arcsin(0.5000) = 30.0000 deg.

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