Square root of 2 the square root of two, with a reasonable small denominator, the fraction (≈ 1.4142857) is sometimes used. The sequence in the OEIS gives the numerical value for the square root of two, truncated to 65 decimal places: The Babylonian clay tablet YBC 7289 (c. 1800–1600 BC) gives an approximation of in four sexagesimal figures, , which is accurate to about six decimal digits, and is the closest possible three-place sexagesimal representation of : Another early close approximation is given in ancient Indian mathematical texts, the Sulbasutras (c. 800–200 BC) as follows: "Increase the length [of the side] by its third
Square root of a 2 by 2 matrix denominator "t" be zero. The formula above fails completely if "δ" and "τ" are both zero; that is, if "D" = −"A" and "A" = −"BC", so that both the trace and the determinant of the matrix are zero. In this case, if "M" is the null matrix (with "A" = "B" = "C" = "D" = 0), then the null matrix is also a square root of "M", as are for any real or complex values of "b" and "c". Otherwise "M" has no square root. If "M" is diagonal (that is, "B" = "C" = 0), one can