Finding Roots with a Scientific Calculator

Date: 05/15/2000 at 00:11:09
From: Tom Pickett
Subject: 8th Root of a Number

How do you calculate the 8th root of a number using a scientific 
calculator? Also, how do you do any other roots besides the square 
root using a calculator?

Date: 05/15/2000 at 08:54:42
From: Doctor Rick
Subject: Re: 8th Root of a Number

Hi, Tom -

The 8th root can be calculated pretty simply: just press the square 
root key 3 times. That's because the square of the square of a number 
is the 4th power of the number, and the square of the 4th power is the 
8th power.

In general, the nth root of a number is the same as the (1/n)th power 
of the number. Your calculator probably has a key marked "x to the y 
power" in some fashion (I'll write it "x^y"), as well as a key marked 
"1/x" . If it has the same operation precedence rules as my 
calculator, you can enter:

     256  [x^y]  8  [1/x]  [=]

to get the 8th root of 256. What you've just calculated (if it works 
correctly) is

     1/8
  256    = 2

If it doesn't work correctly, you might need to put parentheses around 
the (8 [1/x]).

- Doctor Rick, The Math Forum
  http://mathforum.org/dr.math/