The geometric mean of a and b is this operation applied to a times b.
Viète's formula for two over pi uses the iterated composition of this operation. The Bhaskara-Brouncker algorithm and the Babylonian method compute this operation. Newton's method applied to the formula "x squared plus c" finds this (*) function for c. The geometric mean of a and b is this operation applied to a times b. When this operation is applied to negative one, the result is i. For 10 points, name this operation on a number n, that returns the number m such that m squared is n.
Viète's formula for two over pi uses the iterated composition of this operation.
{square root}