c# - Why does Math.Pow(-78.0921, -64.6294) return NaN? -

i have 2 values: x = -78.0921 , y = -64.6294. now, when want compute math.pow(x, y) returns nan. should do? how can solve problem?

how should calculate power? there other function can calculate this?...or maybe not defined mathematically ?

you've tried compute number not real.

by not real mean, if tried every single number between largest number , smallest number can think of, none of numbers solution -78.0921 power of -64.6294.

in fact, no real number solution -1 power of 0.5, or square root of -1, , in general a^b if negative , b non-integer, the result not real.

the inability express such useful result in real numbers lead invention of complex numbers. sqrt(-1) = i, imaginary unit, in complex number system - complex numbers have real component , imaginary component, expressed a + b*i.

in general, no negative number fractional power produces real result, have component of in - closer .5 power is, more i, closer .0, more real, , path follows circle between real , imaginary, e.g.

-1^x = cos(pi*x)+i*sin(pi*x)

read more complex numbers: http://en.wikipedia.org/wiki/complex_number

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if wish work complex numbers in c#, try http://msdn.microsoft.com/en-us/library/system.numerics.complex.aspx

however, unless complex numbers have meaning in problem domain (they meaningful in many electrical engineering, physics , signal analysis problems, example) it's possible data wrong or logic wrong attempting such thing in first place.