# What is the argument of this function?

So, Im trying to get the arg of -2x^t, for t between 0 and 1, but I dont know how to get a general expression for this. To note that x>0 in R. (I tagged complex but I dont really know what to put there in this case, since its about the arg but only in R).

• Arg only define for complex number( or two dimension point),what are you want to do with -2x^t ? Commented Sep 5, 2022 at 2:33

I'm trying to get the arg of -2x^t, for t between 0 and 1

ClearAll[x, t]
Assuming[Element[t, Reals] && x > 0, Simplify[Arg[-2*x^t]]]


Notice no need to tell it that $$t>0$$ or $$t<0$$. It makes no difference since $$x$$ is real. You can also use the shorter version:

 Assuming[{t > 0, x > 0}, Simplify[Arg[-2*x^t]]]


Since by saying $$x>0$$, then the assumption of real is automatically added, since > only works for real values, not complex. Same for $$t>0$$. In the second version above $$t>0$$ is there just to tell it that $$t$$ is real. Same result is obtained for $$t<0$$.

Using Refine:

Refine[Arg[-2*x^t], {x > 0, t > 0}]
(*π*)