Square root any nonnegative number, then the principal square root of −"x" is The right side (as well as its negative) is indeed a square root of −"x", since For every non-zero complex number "z" there exist precisely two numbers "w" such that : the principal square root of "z" (defined below), and its negative. There are two complex numbers that square to a given arbitrary non-zero imaginary number formula_11 with real formula_12 where the two-digit pattern {3, 6} repeats over and over again in the partial denominators. Since , the above is also identical to the following generalized continued fractions: The
Square root biased sampling the average person to be a security risk, then when using square root biased sampling, people from the profiled group would be screened three times more often than the average person. Press developed square root biased sampling as a way to sample long sequences of DNA. It had also been developed independently by Ruben Abagyan, a professor at TSRI in La Jolla, California, for use in a different biological context. An even earlier discovery was by Martin L. Shooman, who used square root biased sampling in a test apportionment model for software reliability. Press' later proposal to use square root