num pow(num x, num exponent)

Returns x to the power of exponent.

If x is an int and exponent is a non-negative int, the result is an int, otherwise both arguments are converted to doubles first, and the result is a double.

For integers, the power is always equal to the mathematical result of x to the power exponent, only limited by the available memory.

For doubles, pow(x, y) handles edge cases as follows:

  • if y is zero (0.0 or -0.0), the result is always 1.0.
  • if x is 1.0, the result is always 1.0.
  • otherwise, if either x or y is NaN then the result is NaN.

  • if x is negative (but not -0.0) and y is a finite non-integer, the result is NaN.

  • if x is Infinity and y is negative, the result is 0.0.
  • if x is Infinity and y is positive, the result is Infinity.
  • if x is 0.0 and y is negative, the result is Infinity.
  • if x is 0.0 and y is positive, the result is 0.0.

  • if x is -Infinity or -0.0 and y is an odd integer, then the result is -pow(-x ,y).

  • if x is -Infinity or -0.0 and y is not an odd integer, then the result is the same as pow(-x , y).

  • if y is Infinity and the absolute value of x is less than 1, the result is 0.0.

  • if y is Infinity and x is -1, the result is 1.0.

  • if y is Infinity and the absolute value of x is greater than 1, the result is Infinity.

  • if y is -Infinity, the result is 1/pow(x, Infinity).

This corresponds to the pow function defined in the IEEE Standard 754-2008.

Notice that an int result cannot overflow, but a double result might be double.INFINITY.

Source 

external num pow(num x, num exponent);