F.9.1.4 The atan2 functions

1

  • atan2((+-)0, -0) returns (+-)pi .[1]

  • atan2((+-)0, +0) returns (+-)0.

  • atan2((+-)0, x) returns (+-)pi for x < 0.

  • atan2((+-)0, x) returns (+-)0 for x > 0.

  • atan2(y, (+-)0) returns -pi /2 for y < 0.

  • atan2(y, (+-)0) returns pi /2 for y > 0.

  • atan2((+-)y, -(inf)) returns (+-)pi for finite y > 0.

  • atan2((+-)y, +(inf)) returns (+-)0 for finite y > 0.

  • atan2((+-)(inf), x) returns (+-)pi /2 for finite x.

  • atan2((+-)(inf), -(inf)) returns (+-)3pi /4.

  • atan2((+-)(inf), +(inf)) returns (+-)pi /4.

Footnotes