1. Not finding help here? Sign up for a free 30min 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!

How do you solve -1<2x^2-x<1?

  1. Mar 8, 2012 #1
    1. The problem statement, all variables and given/known data

    -1<2x[itex]^{2}[/itex]-x<1

    2. Relevant equations



    3. The attempt at a solution

    I can't seem to solve this.. I am in calculus but I get to this point at the end of a long question, and it seems so trivial that I didn't think it would be a good idea to post this in the calculus forum.

    How do you solve this? I know (from wolframalpha) that the answer is -1/2<x<1 but I don't know how it got this.
     
  2. jcsd
  3. Mar 8, 2012 #2

    Mark44

    Staff: Mentor

    The inequality is equivalent to
    0 < 2x2 - x + 1 < 2,
    which is the same as these two inequalities:
    0 < 2x2 - x + 1 AND 2x2 - x + 1 < 2

    Do you know how to solve these quadratic inequalities?

    Graphically, the solution set to your inequality is the set of x values on the graph of y = 2x2 - x for which -1 < y < 1.
     
  4. Mar 8, 2012 #3
    OK thanks! Splitting it up into two inequalities really makes it much easier to think about.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: How do you solve -1<2x^2-x<1?
  1. How do you solve this? (Replies: 17)

  2. Solve for x: 2x-x^2=3 (Replies: 10)

Loading...