I have a code like this: (I used the font mtpro2.)
\renewcommand{\arraystretch}{1.6}
\begin{tabular}{p{8cm}l}
\multicolumn{2}{l}{(a)~$\left( \frac{81}{16}\right)^{-0.25}\times \left( \frac{8}{27}\right) ^{-\frac{2}{3}}\times (0.25)^{-2.5}+\left(\sqrt{243\sqrt{3}}\right)^{\frac{1}{11}}\times (\sqrt{3})^{-1}=?$} \\
(b)~$\sqrt[3]{a^{\frac{9}{2}}\sqrt{a^{-3}}}\div \sqrt{\sqrt[3]{a^{-7}}\cdot \sqrt[3]{a}}=?$ & (c)~$(5+2\sqrt{6})^{2000}\cdot (5-2\sqrt{6})^{1999}$ \\
(d)~$\sqrt[a-b]{x^{\frac{b+c}{c-a}}}\sqrt[b-c]{x^{\frac{c+a}{a-b}}}\sqrt[c-a]{ x^{\frac{a+b}{b-c}}}=?$ &(e)~$(x^{\frac{2}{3}}+x^{-\frac{2}{3}}+1)(x^{\frac{2}{3}}-x^{-\frac{2}{3}})(x-x^{-1})^{-1}=?$
\end{tabular}
How can I make the superscript higher and a little bigger? For example, the orangle part in (d). I've tried throwing \displaystyle in the sub formula in \sqrt{}, but it wasn't lift up much. By the way, I use \renewcommand{\arraystretch}{1.6} to lengthen the lineskip in my tabular environment. Is my method good enough? Is there another proper way to do the same thing?



x^{(b+c)/(c-a)}an option? – Steven B. Segletes Mar 31 '17 at 12:29x^{\nicefrac{(b+c)}{c-a}}(from packagenicefrac) then? (I actually use a simple macro for a similar slanted but vertically offset fraction, mainly inline). – Chris H Mar 31 '17 at 12:32\phantomsubscript could apply here: http://tex.stackexchange.com/a/123946/579 – barbara beeton Mar 31 '17 at 12:37