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Linear Algebra - Cubic Equation from Given Points

by Cod
Tags: algebra, cubic, equation, linear, points
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Sep9-10, 06:08 PM
P: 308
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.
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Sep9-10, 07:30 PM
Sci Advisor
PF Gold
P: 39,569
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.
Sep9-10, 08:30 PM
P: 308
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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