Finding quadratic function from two points and known max value
08-31-2017, 12:57 PM
Post: #1
 Dave Britten Senior Member Posts: 1,928 Joined: Dec 2013
Finding quadratic function from two points and known max value
I need to work this into a C# program for generating points along an arc, and the math is making me cross-eyed.

Essentially, I know two points on the parabola, I know the y value of the maximum (but not x), and I know that the second derivative is negative, i.e. the coefficient of x^2 is negative. All the typical approaches of treating it as a system of 3 linear equations seem to rely on having three known points, but I've got two, plus an additional equation 2*a*x_3+b=0 where x_3 is unknown.

Is there a straight-forward way of tackling this without pulling a bunch of numeric and matrix libraries into the program?
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 Messages In This Thread Finding quadratic function from two points and known max value - Dave Britten - 08-31-2017 12:57 PM RE: Finding quadratic function from two points and known max value - grsbanks - 08-31-2017, 01:03 PM RE: Finding quadratic function from two points and known max value - Dave Britten - 08-31-2017, 01:09 PM RE: Finding quadratic function from two points and known max value - Nigel (UK) - 08-31-2017, 02:46 PM RE: Finding quadratic function from two points and known max value - Dave Britten - 08-31-2017, 05:02 PM RE: Finding quadratic function from two points and known max value - Dave Britten - 08-31-2017, 05:31 PM

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