• Syntax: \left.{...\right}  (note the dot!)
• Ex.: $$\left.{{\rm~term1\atop\rm~term2}\right}=y$$ gives

$\left.{{\rm~term1\atop\rm~term2}\right}=y$

(\rm~something switches to roman style)

• Syntax: \sqrt[n]{arg} or simply  \sqrt{arg} for \sqrt[2]{arg}
• Ex.: $$\sqrt[3]{8}$$ gives

$\sqrt[3]{8}$

• Ex.: $$\sqrt{-1}$$ gives

$\sqrt{-1}$

• Nesting of roots (and combining with fractions, ...etc.) are possible.
• Ex.: $$\sqrt[n]{\frac{x^n-y^n}{1+u^{2n}}}$$ gives

$\sqrt[n]{\frac{x^n-y^n}{1+u^{2n}}}$

• Ex.: $$\sqrt[3]{-q+\sqrt{q^2+p^3}}$$ gives

$\sqrt[3]{-q+\sqrt{q^2+p^3}}$