Math.. forming a quadratic function given three points.
2007-08-22 11:03:13 · 4 answers · asked by Ricardo C 1 in Science & Mathematics ➔ Mathematics
y = x^2 - 6x + 5
You use linear regression, but I haven't done one of those by hand since college. The method above (3 simultaneous equations, 3 variables), also works.
Anymore, there are powerful software tools (like Excel chart trendlines) that can solve it for you.
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2007-08-22 11:12:05 · answer #1 · answered by tlbs101 7 · 0⤊ 0⤋
If your quadratic is y = ax2 + bx + c, write three equations given your 3 points. Then you can solve these for a, b and c. The first equation would be 5= 0 + 0 + c. That gives you c, so you reduce your work accordingly.
2007-08-22 18:09:59 · answer #2 · answered by cattbarf 7 · 1⤊ 0⤋
Plug them each into the quadratic equation and basically solve for each variable using either systems of equations or the matrix function on your calculator.
2007-08-22 18:12:42 · answer #3 · answered by crystal 2 · 0⤊ 0⤋
If i remember correctly, just use 2 of the three.
You should try two different combos and see if you can come up with more info, im about to look on the web
2007-08-22 18:09:58 · answer #4 · answered by Cabba 2 · 0⤊ 0⤋