How is pow() calculated in C?

Question

Our professor said that you can\'t calculate a^b if a<0 using pow() because pow() uses natural logarithms to calculate it (a^b

Answer 1

pow does work for negative numbers. It just doesn't work when the base is negative and the exponent is not an integer.

A number in the form a^x/y actually involves the y-th root of x. For instance, when you try to calculate a^1/2 you are actually looking for the square root of a.

So what happens if you have a negative base and a non-integer exponent? You get a y-th root of a negative number, which yields is a complex non-real number. pow() does not work with complex numbers, so it will probably return NaN.