The '^' character means "raise a number to a power". For example,
3^2 = 3 * 3 = 9
2^3 = 2 * 2 * 2 = 8
For roots of a number, such as the square or cube root, you use (1/N) where
N is the root you want to return. For example,
9 ^ (1/2) = 3
8 ^ (1/3) = 2
16 ^ (1/4) = 2
In the formula you posted, the sub-part
(F6/B6)^(1/4)
divides F6 by B6 and then takes the 4th root of that quotient.
--
Cordially,
Chip Pearson
Microsoft MVP - Excel, 10 Years
Pearson Software Consulting
www.cpearson.com
(email on the web site)