that seems work, thankyou.
but... there may be a situation where you can't use surd. I am looking for examples.
j:= x-> x^2.875
now i have problems with complex numbers
evalf(j(-2)) comes out complex answer
So i have to turn 2.875 into a rational number.
j(-2) gave me
Oh nevermind, surd(x,8) is not defined for x<0 reals anyway.
which is complex
There are also possible problems if you raise a number to a square root
m:= x-> x^cuberoot 3
Also what exactly is the definition of the principal cube root of -1, it is necessarily a complex number?
I know the principal square root of 4 is 2.
Does (RealDomain); get you the same result with fractional exponents? I tried it and got a messy expression with signum's everywhere.
Also odd is the fact
evalf(surd(-2,8)) does not equal evalf((-2)^(1/8))
shouldn't they be equal since if x < 0 , the surd becomes complex
does not simplify as well as your expression