Linear Algebra - Cubic Equation from Given Points

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Linear Algebra -- Cubic Equation from Given Points

Homework Statement



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

Homework Equations



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

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

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:
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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.
 


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.
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
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