Results 1 to 10 of 10

Math Help - Rationalizing the Denominator

  1. #1
    Newbie
    Joined
    Sep 2008
    Posts
    9

    Rationalizing the Denominator

    This is a problem that i'm not sure if i finished it or does it still got more steps? thanks

    If you can't see the image then click this link.
    http://img235.imageshack.us/my.php?i...1076157en5.png
    Attached Thumbnails Attached Thumbnails Rationalizing the Denominator-untitled.bmp  
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Moo
    Moo is offline
    A Cute Angle Moo's Avatar
    Joined
    Mar 2008
    From
    P(I'm here)=1/3, P(I'm there)=t+1/3
    Posts
    5,618
    Thanks
    6
    Hello,
    Quote Originally Posted by xJenniferx View Post
    This is a problem that i'm not sure if i finished it or does it still got more steps? thanks

    If you can't see the image then click this link.
    ImageShack - Hosting :: 91076157en5.png
    \frac{4}{\sqrt{xy}}\cdot\frac{\sqrt{xy}}{\sqrt{xy}  }=\frac{4}{xy} ??

    I think you forgot \sqrt{xy} in the numerator and you can't go further...
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Sep 2008
    Posts
    9
    so i stop at 4 / xy and forget the (2)(2)/xy?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Nox
    Nox is offline
    Newbie
    Joined
    Sep 2008
    Posts
    11
    I don't think you needed to reduce 4 to "(2)(2)," but that's right for the most part. You did forget the \sqrt{xy} in the numerator, though.

    Have you talked about absolute values yet in class? If so, think of how \sqrt{x^2} isn't exactly the same as x. If you haven't gotten that far yet in your class, never mind; you did it just fine.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Moo
    Moo is offline
    A Cute Angle Moo's Avatar
    Joined
    Mar 2008
    From
    P(I'm here)=1/3, P(I'm there)=t+1/3
    Posts
    5,618
    Thanks
    6
    Quote Originally Posted by xJenniferx View Post
    so i stop at 4 / xy and forget the (2)(2)/xy?
    Yes

    But it's \frac{4 \sqrt{xy}}{xy}, not [tex]\frac{4}{xy}[/Math]
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Newbie
    Joined
    Sep 2008
    Posts
    9
    if we did do absolute value what do i need to change? can't find where i will have to do with x^2
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Moo
    Moo is offline
    A Cute Angle Moo's Avatar
    Joined
    Mar 2008
    From
    P(I'm here)=1/3, P(I'm there)=t+1/3
    Posts
    5,618
    Thanks
    6
    Quote Originally Posted by xJenniferx View Post
    if we did do absolute value what do i need to change? can't find where i will have to do with x^2
    By writing \sqrt{xy} at the very beginning, you already "supposed" xy>0.
    But it's always better to write this down
    Follow Math Help Forum on Facebook and Google+

  8. #8
    Nox
    Nox is offline
    Newbie
    Joined
    Sep 2008
    Posts
    11
    EDIT: Moo's right. Haha. Neither x nor y could be negative (technically, both could be negative... but they'd cancel out in the last step), so absolute value signs are redundant.
    Follow Math Help Forum on Facebook and Google+

  9. #9
    Moo
    Moo is offline
    A Cute Angle Moo's Avatar
    Joined
    Mar 2008
    From
    P(I'm here)=1/3, P(I'm there)=t+1/3
    Posts
    5,618
    Thanks
    6
    Quote Originally Posted by Nox View Post
    It's tricky. Since you multiplied \sqrt{xy} by \sqrt{xy}, you'd have \sqrt{x^2y^2}, which comes out to | x|*| y|. My guess is, if you're under 10th or 11th grade or so and/or you haven't gotten to Algebra II, you probably haven't discussed this, and you really needn't worry about it.
    no.
    It is enough that xy is positive. You don't need to take the absolute values of x and y (though it is not incorrect). I mean it is not useful to write |x| |y|.
    Follow Math Help Forum on Facebook and Google+

  10. #10
    Nox
    Nox is offline
    Newbie
    Joined
    Sep 2008
    Posts
    11
    I know. :P I just didn't think of it before. See the EDIT.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Rationalizing Denominator
    Posted in the Calculus Forum
    Replies: 2
    Last Post: July 21st 2011, 11:59 AM
  2. Rationalizing the Denominator
    Posted in the Algebra Forum
    Replies: 1
    Last Post: February 2nd 2009, 08:13 AM
  3. Rationalizing the Denominator
    Posted in the Algebra Forum
    Replies: 2
    Last Post: January 23rd 2009, 10:43 PM
  4. Rationalizing the Denominator #2
    Posted in the Algebra Forum
    Replies: 4
    Last Post: September 10th 2008, 01:57 PM
  5. Rationalizing a Denominator
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: December 14th 2007, 08:44 AM

Search Tags


/mathhelpforum @mathhelpforum