Results 1 to 14 of 14

Math Help - radicals expression

  1. #1
    Senior Member
    Joined
    Jul 2010
    Posts
    427
    Thanks
    5

    radicals expression

    Hi All;
    I have two solutions to the problem 9x^2 + 2sqrt3y - 3x^2sqrt3y they are

    6x^2 + sqrt3y and 6x^2sqrt3y.

    Please let me know which is right and how we got there.

    Thanks.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Prove It's Avatar
    Joined
    Aug 2008
    Posts
    11,829
    Thanks
    1602
    What you posted isn't even an equation, how can it have solutions?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member
    Joined
    Jul 2010
    Posts
    427
    Thanks
    5
    Oops I meant simplified versions.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member
    Joined
    Dec 2009
    Posts
    226
    Is 9x^2 + 2\sqrt{3y} - 3x^2\sqrt{3y} the expression in which you are interested? If so, then neither of the "simplifications" are equal to the original expression. In fact, the original expression can't be simplified much (if at all).
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Senior Member
    Joined
    Jul 2010
    Posts
    427
    Thanks
    5
    The simplification on a web site is 6x^2sqrt3y.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Member
    Joined
    Dec 2009
    Posts
    226
    What website? WolframAlpha doesn't offer any such expression as an equal expression.
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Senior Member
    Joined
    Jul 2010
    Posts
    427
    Thanks
    5
    in browser search type (simplify radicals variables exponents) and scroll to the first pdf and its a question at the bottom at the bottom.
    Problem 5.
    Follow Math Help Forum on Facebook and Google+

  8. #8
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    10,211
    Thanks
    419
    Awards
    1
    Quote Originally Posted by anthonye View Post
    in browser search type (simplify radicals variables exponents) and scroll to the first pdf and its a question at the bottom at the bottom.
    Problem 5.
    Do you know how many search engines there are on the net? Give a link or something, will you?

    However, no matter what the link is the only thing that can be done with this is
    9x^2 + 2 \sqrt{3y} - 3x^2 \sqrt{3y} = 9x^2 + (2 - 3x^2)\sqrt{3y}

    or
    9x^2 + 2 \sqrt{3y} - 3x^2 \sqrt{3y} = 3x^2(3 - \sqrt{3y} ) + 2 \sqrt{3y}

    -Dan
    Follow Math Help Forum on Facebook and Google+

  9. #9
    Senior Member
    Joined
    Jul 2010
    Posts
    427
    Thanks
    5
    Follow Math Help Forum on Facebook and Google+

  10. #10
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,959
    Thanks
    1781
    Awards
    1
    Quote Originally Posted by anthonye View Post
    The problem is 4x\sqrt{12x^2y}+\sqrt{3x^4y}-x^2\sqrt{3y}

    I know how the got their answer. BUT it is wrong.
    If you look at that expression we see that y\ge 0 but x can be any real number.

    Now why is it incorrect? Let x=-3~\&~y=3 the given expression evaluates to 270.
    BUT 6x^2\sqrt{3y}=162. To be equal the values must be the same.
    Here is the mistake. They said 4x\sqrt{12x^2y}=8x^2\sqrt{3y}. BUT IT DOES NOT.
    This is what is correct: 4x\sqrt{12x^2y}=8x|x|\sqrt{3y}.
    Follow Math Help Forum on Facebook and Google+

  11. #11
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    10,211
    Thanks
    419
    Awards
    1
    Should I ask why the original post had nothing to do with this, or would it be smarter to leave it alone?

    -Dan
    Follow Math Help Forum on Facebook and Google+

  12. #12
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,959
    Thanks
    1781
    Awards
    1
    Quote Originally Posted by topsquark View Post
    Should I ask why the original post had nothing to do with this, or would it be smarter to leave it alone?-Dan
    My guess is that the poster does not understand enough about radicals to post readable symbols.
    Follow Math Help Forum on Facebook and Google+

  13. #13
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    10,211
    Thanks
    419
    Awards
    1
    Quote Originally Posted by Plato View Post
    My guess is that the poster does not understand enough about radicals to post readable symbols.
    (snorts) That does it, I'm going back to my Bible study...

    -Dan
    Follow Math Help Forum on Facebook and Google+

  14. #14
    Senior Member
    Joined
    Jul 2010
    Posts
    427
    Thanks
    5
    Ok thanks for the help everyone are there any sites that can be recommended that I can visit to learn/pratice more radicals?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 20
    Last Post: January 15th 2012, 10:30 AM
  2. Replies: 6
    Last Post: October 6th 2011, 02:48 PM
  3. Replies: 4
    Last Post: February 9th 2010, 06:22 PM
  4. Help with radicals :(
    Posted in the Algebra Forum
    Replies: 2
    Last Post: December 2nd 2009, 09:20 PM
  5. Radicals
    Posted in the Algebra Forum
    Replies: 2
    Last Post: February 14th 2008, 12:02 PM

Search Tags


/mathhelpforum @mathhelpforum