Raising something to the 1/4th power is the same as applying the 4th root to that expression. Raising an expression to the 1/n power is the same as applying the nth root.
Rule: [tex]x^{1/n} = \sqrt[n]{x} [/tex] (if the text is too small it basically says x to the (1/n) = square root with a small 'n' all over x)
