\(\displaystyle x^2-i=0\)

\(\displaystyle x^2=i\)

\(\displaystyle x=\sqrt{i}\)

\(\displaystyle x=\sqrt{\sqrt-1}\)

\(\displaystyle x=\pm(\frac{1+i}{\sqrt2})\)

What symbol(s) is(are) needed to make Delimiters (. . .) bigger to completely encompass fraction?