1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Doing Fractional Exponents on Basic Scientific Calculator

  1. Nov 28, 2015 #1
    Suppose you have 8-1/3 and want a precise value for it. How would you go about calculating this on a regular scientific calculator.

    I punched in:

    8, then the exponent button, then 1, then negative, then division, and finally 3. The calculator reads "error."
  2. jcsd
  3. Nov 29, 2015 #2


    User Avatar
    2017 Award

    Staff: Mentor

    Use -0.33333... with as many digits as your calculator accepts. The error will be comparable to usual rounding errors, and the calculator would not calculate it more precisely even if you find a way to enter "-1/3".
  4. Nov 30, 2015 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    It's not clear what a 'regular scientific calculator' means. Some calculators use algebraic entry; some use reverse Polish notation (primarily the HP brand).

    This is a question which is best left up to the user's manual.

    In any calculator, you can always use logs to calculate 8-1/3.

    log (8-1/3)) = -(1/3) log (8) = -log (8) / 3. The answer is then 10-log(8)/3

    You can also use natural logs and ex to convert the natural log back into a number.
  5. Dec 1, 2015 #4


    User Avatar
    Science Advisor

    Or you could just enter "1/2" to begin with!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook