Results 1 to 8 of 8

Math Help - Find a polynomial function that has the given zeros

  1. #1
    Newbie
    Joined
    Mar 2013
    From
    u.s
    Posts
    17

    Find a polynomial function that has the given zeros

    Please don't ignore this, I really need help. Sorry for making 2 threads in one day, I solved the other problem. This will be the last thread I make on here for a while, possibly months since next week is my last week of uni.

    Find a polynomial function with real coefficients that has the given zeros:

    5, -4+2i, -4-2i


    please help, and thank YOU in advance!!!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    9,845
    Thanks
    320
    Awards
    1

    Re: Find a polynomial function that has the given zeros

    Quote Originally Posted by captaincrunch383 View Post
    Please don't ignore this, I really need help. Sorry for making 2 threads in one day, I solved the other problem. This will be the last thread I make on here for a while, possibly months since next week is my last week of uni.

    Find a polynomial function with real coefficients that has the given zeros:

    5, -4+2i, -4-2i


    please help, and thank YOU in advance!!!
    First, why would we ignore it? Second you can post as many problems as you like, as long as you are working on them.

    If a polynomial has complex zeros then they must come in complex conjugate pairs. Your complex zeros are complex conjugates so that works out.

    You know three zeros. So your polynomial will be of the form: (x - r_1 )(x - r_2 )(x - r_3 ) where the r's are the zeros of the polynomial.

    See what you are able to do with that.

    -Dan
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Mar 2013
    From
    u.s
    Posts
    17

    Re: Find a polynomial function that has the given zeros

    Quote Originally Posted by topsquark View Post
    First, why would we ignore it? Second you can post as many problems as you like, as long as you are working on them.

    If a polynomial has complex zeros then they must come in complex conjugate pairs. Your complex zeros are complex conjugates so that works out.

    You know three zeros. So your polynomial will be of the form: (x - r_1 )(x - r_2 )(x - r_3 ) where the r's are the zeros of the polynomial.

    See what you are able to do with that.

    -Dan

    Thank you Dan. I'm afraid I still am a little lost, even with the information that you gave me.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,605
    Thanks
    1574
    Awards
    1

    Re: Find a polynomial function that has the given zeros

    Quote Originally Posted by captaincrunch383 View Post
    Thank you Dan. I'm afraid I still am a little lost, even with the information that you gave me.
    It is hard to think that you are asked to do this, but yet you can not do simple algebra!

    Multiply this out: [x-5]\cdot[x-(-4+2i)]\cdot[x-(-4-2i)]~.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Mar 2013
    From
    u.s
    Posts
    17

    Re: Find a polynomial function that has the given zeros

    Quote Originally Posted by Plato View Post
    It is hard to think that you are asked to do this, but yet you can not do simple algebra!

    Multiply this out: [x-5]\cdot[x-(-4+2i)]\cdot[x-(-4-2i)]~.
    apparently i can't do simple algebra mr pluto. how am i supposed to multiply that out? [x-5] * [x+4+2i] * [x+4+2i] --- is that how it looks once the x is factored in? and i dont know how to multiply when it has 3 terms, i know how to do foil though.

    make fun of me all you want sir, but i just want to get this over with.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,605
    Thanks
    1574
    Awards
    1

    Re: Find a polynomial function that has the given zeros

    Quote Originally Posted by captaincrunch383 View Post
    apparently i can't do simple algebra mr pluto. how am i supposed to multiply that out? [x-5] * [x+4+2i] * [x+4+2i] --- is that how it looks once the x is factored in? and i dont know how to multiply when it has 3 terms, i know how to do foil though. make fun of me all you want sir, but i just want to get this over with.
    I assure that I have no reason or desire to make fun of you,

    But the simple fact is, if one does not know simply basic algebra then it is hopeless to try to help you.

    Go back and do middle school algebra.
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Newbie
    Joined
    Mar 2013
    From
    u.s
    Posts
    17

    Re: Find a polynomial function that has the given zeros

    Quote Originally Posted by Plato View Post
    I assure that I have no reason or desire to make fun of you,

    But the simple fact is, if one does not know simply basic algebra then it is hopeless to try to help you.

    Go back and do middle school algebra.

    why can't you just give me the answer? i don't know why you make it so difficult man..
    Follow Math Help Forum on Facebook and Google+

  8. #8
    MHF Contributor
    Prove It's Avatar
    Joined
    Aug 2008
    Posts
    11,404
    Thanks
    1293

    Re: Find a polynomial function that has the given zeros

    Quote Originally Posted by captaincrunch383 View Post
    why can't you just give me the answer? i don't know why you make it so difficult man..
    You seem to have us confused with a homework service. You are expected to complete your own work yourself, we can only give you some guidance in places where you are stuck.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 4
    Last Post: July 10th 2012, 05:46 AM
  2. Fin the zeros of the polynomial function
    Posted in the Algebra Forum
    Replies: 2
    Last Post: May 24th 2011, 10:58 AM
  3. Replies: 4
    Last Post: May 9th 2010, 01:46 PM
  4. Replies: 3
    Last Post: February 15th 2010, 05:40 PM
  5. Find Polynomial given zeros
    Posted in the Algebra Forum
    Replies: 6
    Last Post: September 28th 2007, 02:59 PM

Search Tags


/mathhelpforum @mathhelpforum