sqrt

float  sqrt(float value)

<vector> sqrt(<vector>value)

Returns the square root of value. For vectors, this is done per-component.

Note The square root of a negative number is defined to be zero.

To quote Edgar Rice Burroughs, Pirates of Venus: “I saw that argument was useless and said no more: there is no use arguing with a man who can multiply anything by the square root of minus one”