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).
2 Answers
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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 $t<0$.
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Using Refine:
Refine[Arg[-2*x^t], {x > 0, t > 0}]
(*π*)
answered Sep 5, 2022 at 6:38
Argonly define for complex number( or two dimension point),what are you want to do with-2x^t? $\endgroup$