# Homework Help: Linear Algebra - Cubic Equation from Given Points

1. Sep 9, 2010

### Cod

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. Sep 9, 2010

### HallsofIvy

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.

3. Sep 9, 2010

### Cod

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.