Results 1 to 3 of 3

Math Help - Fractions (Adv)

  1. #1
    Newbie
    Joined
    Jan 2009
    Posts
    2

    Fractions (Adv)



    Taken from another post. How would you evaluate that fraction, or specifically (out of my homework) 4rt(81) [note that the 4 is the n). I got the bright idea that it might be rooted 4 times, but I get rt(3) and my math book says it's simply 3. Please explain.

    Thanks in advance.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member Last_Singularity's Avatar
    Joined
    Dec 2008
    Posts
    157
    Quote Originally Posted by Harness View Post


    Taken from another post. How would you evaluate that fraction, or specifically (out of my homework) 4rt(81) [note that the 4 is the n). I got the bright idea that it might be rooted 4 times, but I get rt(3) and my math book says it's simply 3. Please explain.

    Thanks in advance.
    Observe that x = 81^{1/4} = (81^{1/2})^{1/2} = 9^{1/2} = 3

    So to find x, square root 81 twice, once to get 9 and a second time to get the answer: 3.

    Raising a number to the one-fourth power does not mean that you are square rooting it four times. Instead, it is asking: which number multiplied by itself four times gets you the original number? In other words, which number multiplied by itself four times gets you 81? That number is defined as 81^{1/4}, or 3.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Jan 2009
    Posts
    2
    Quote Originally Posted by Last_Singularity View Post
    Observe that x = 81^{1/4} = (81^{1/2})^{1/2} = 9^{1/2} = 3

    So to find x, square root 81 twice, once to get 9 and a second time to get the answer: 3.

    Raising a number to the one-fourth power does not mean that you are square rooting it four times. Instead, it is asking: which number multiplied by itself four times gets you the original number? In other words, which number multiplied by itself four times gets you 81? That number is defined as 81^{1/4}, or 3.
    Okay, thanks, that makes sense to me
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 0
    Last Post: April 28th 2010, 09:53 AM
  2. SAT fractions
    Posted in the Algebra Forum
    Replies: 4
    Last Post: December 1st 2009, 03:40 PM
  3. Simplifying Fractions over fractions
    Posted in the Algebra Forum
    Replies: 1
    Last Post: January 28th 2009, 10:20 AM
  4. Algebraic fractions with 3 or more fractions
    Posted in the Algebra Forum
    Replies: 2
    Last Post: November 19th 2008, 02:52 AM
  5. simplifing fractions over fractions
    Posted in the Algebra Forum
    Replies: 1
    Last Post: December 16th 2007, 01:57 PM

Search Tags


/mathhelpforum @mathhelpforum