In addition to squares and cubes, certain other powers and roots may be
readily obtained with the slide rule.
_Two-thirds Power._—The value of N^⅔ is found on A over ∛̅N on D. The
number of digits is decided by the rule for squares, working from the
number of digits in the cube root. It will often be found preferable to
treat N^⅔ as N ÷ ∛̅N, as in this way the magnitude of the result is much
more readily appreciated.
_Three-two Power._—N^{³⁄₂} can be obtained by cubing the square root,
deciding the number of digits in each process. For the reason just
given, it is preferable to regard N^{³⁄₂} as N × √̅N.
_Fourth Power._—For N^4 set the index of C to N on D and over N on C
read N^4 on A; or find the square of the square of N, deciding the
number of digits at each step.
_Fourth Root._—Similarly for ∜̅N, take the square root of the square
root.
_Four-third Power._—N^{⁴⁄₃} = N^{1·33} (useful in gas-engine diagram
calculations) is best treated as N × ∛̅N.
Other powers can be found by repeated multiplication. Thus setting 1 on
B to N on A, we have on A, N^2 over N; N^3 over N^2; N^4 over N^3; N^5
over N^4, etc. In the same way, setting N on B to N on D, we can read
such values as N^¾, N^⅞, etc.