13th root 13th root of a 100-digit number. All world records for mentally extracting a 13th root have been for numbers with an integer root. 13th root Extracting the 13th root of a number is a famous category for the mental calculation world records. The challenge consists of being given a large number (possibly over 100 digits) and asked to return the number that, when taken to the 13th power, equals the given number. For example, the 13th root of 8,192 is 2 and the 13th root of 96,889,010,407 is 7. Extracting the 13th root has certain properties. One is that the
Square root of 2 is related to the property of silver ratios. if the square root symbol is interpreted suitably for the complex numbers and . for square roots and only one minus sign. Similar in appearance but with a finite number of terms, appears in various trigonometric constants: It is not known whether is a normal number, a stronger property than irrationality, but statistical analyses of its binary expansion are consistent with the hypothesis that it is normal to base two. The identity , along with the infinite product representations for the sine and cosine, leads to products such as and or equivalently,