Results 1 to 7 of 7

Math Help - rolle's theorem help

  1. #1
    Newbie
    Joined
    Nov 2009
    Posts
    21

    rolle's theorem help

    determine if Rolle's Theorem can be applied. If the theorem can be applied, find all c values.

    f(x) = x^2 - 1 / x [-1, 1]

    I've done a few of these, but I am very confused about this one.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    May 2009
    Posts
    211
    First you want to make sure that f(1) = f(-1), Then make sure that the function is continuous on [-1,1], and differentiable on (-1,1)
    Then if those conditions hold, you can apply Rolle's theorem.
    Then find f'(x), and find for what x value or values does f'(x)=0.
    Last edited by Arturo_026; November 22nd 2009 at 11:59 AM.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Nov 2009
    Posts
    186
    Does the rolle theorem state, it can be applied if the function is continuous and is differentiable at x = 0, then you can apply the theorem?

    This function is undefined at x = 0, I am not too familiar with it so perhaps you can shed some light for me
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member
    Joined
    May 2009
    Posts
    211
    Quote Originally Posted by RockHard View Post
    Does the rolle theorem state, it can be applied if the function is continuous and is differentiable at x = 0, then you can apply the theorem?

    This function is undefined at x = 0, I am not too familiar with it so perhaps you can shed some light for me
    You are right!. I didn't notice the x in the denominator.
    Yes, since Rolle's theorem asks for the function to be continuos on [a,b] and differentiable on (a.b), then it cannot be applied in this function.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member
    Joined
    Nov 2009
    Posts
    186
    Ah, so both condition's must hold true in order to apply the theorem? Thanks for the confirmation arturo.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Newbie
    Joined
    Nov 2009
    Posts
    21
    well, the problem's directions say exactly this:

    determine wether Rolle's Theorem can be applied to f on the losed interval [a,b]. If Rolle's Theorem can be applied, find all values of c in the open interval (a,b) such that f'(c)=0.

    I just don't understand calculus really at all, if you want the honest truth. About 80% of my calc. AP class doesnt get whats going on because of the teacher. He says we need to do research and figure out our own ways of doing this, yet still grades us on wether or not we get it right. I'm only taking this class because it looks great on a college app. I'm stressing so bad over here.
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Member
    Joined
    Nov 2009
    Posts
    186
    It says determine if Rolle's Theorem can be applied, it cannot be here, thanks to Arturo's confirmation. So you simply state Rolle's Theorem cannot be applied here because the function is discontinuous at x = 0 on the interval [-1,1]
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Rolle's Theorem
    Posted in the Calculus Forum
    Replies: 1
    Last Post: October 11th 2009, 11:28 AM
  2. Rolle's Theorem
    Posted in the Calculus Forum
    Replies: 1
    Last Post: September 16th 2009, 08:09 PM
  3. intermediate value theorem/rolle's theorem
    Posted in the Calculus Forum
    Replies: 6
    Last Post: December 8th 2007, 02:55 PM
  4. Rolle's Theorem Help :D
    Posted in the Calculus Forum
    Replies: 1
    Last Post: October 18th 2007, 10:38 AM
  5. Rolle's theorem
    Posted in the Calculus Forum
    Replies: 2
    Last Post: April 24th 2007, 02:21 PM

Search Tags


/mathhelpforum @mathhelpforum