Try to plot x^(2/3).. what happen for x<0 ? - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html) +--- Forum: HP Prime (/forum-5.html) +--- Thread: Try to plot x^(2/3).. what happen for x<0 ? (/thread-13489.html) Try to plot x^(2/3).. what happen for x<0 ? - josephec - 08-22-2019 03:45 AM Hi Friends Why In HP PRIME is different (X^2)^(1/3) and (x^(1/3))^2 ? Pd. The first one plots for x<0 Thanks for Your answers. RE: Try to plot x^(2/3).. what happen for x<0 ? - rkf - 08-22-2019 06:45 AM I assume the Prime does simpy follow the basic rules of Mathematics: In the first expression, we start with squaring x, which yields for all reals a positive result - thus the cubic root is defined everywhere. In the second expression, the cubic root is calculated first - but for reals is only defined for x >= 0. Thus the plot is left for x < 0. RE: Try to plot x^(2/3).. what happen for x<0 ? - ijabbott - 08-22-2019 08:08 AM You can redefine the second one as $$\big( \sqrt[3]{x}\big)^2$$ to square the real cube root of $$x$$. Note that $$x^\frac{1}{3}$$ and $$\sqrt[3]{x}$$ are treated differently, and that $$x^\frac{1}{3}$$ usually produces a complex number when $$x < 0$$, and its square is also complex, so it cannot be plotted by the Function app.