Linear Algebra - Cubic Equation from Given Points

  1. Linear Algebra -- Cubic Equation from Given Points

    1. The problem statement, all variables and given/known data

    Find the equation to the third polynomial that flows through the given points: (0,1); (1,0); (-1,0); (2, -15).

    2. Relevant equations

    f(t) = a + bt + ct^2 + dt^4

    Need to find a, b, c, and d.

    3. The attempt at a solution

    See attachment. When I plug my answer back in, it obviously doesn't work; however, I cannot figure out where I missed up the matrix.

    Any help is greatly appreciated.
     
    Last edited: Sep 9, 2010
  2. jcsd
  3. HallsofIvy

    HallsofIvy 40,544
    Staff Emeritus
    Science Advisor

    Re: Linear Algebra -- Cubic Equation from Given Points

    There is an error in the last column of your third matrix. You did not subtract 1 in the last column. It should be 0 2 4 8 -16, not -15.
     
  4. Re: Linear Algebra -- Cubic Equation from Given Points

    Thanks for catching that mistake. Found another algebra mistake in another matrix, but all in all, I figured everything out. Thanks again for pointing out my miscue.
     
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