My Math Forum Curve fitting.

 Algebra Pre-Algebra and Basic Algebra Math Forum

 December 30th, 2007, 08:08 AM #1 Newbie   Joined: Dec 2007 Posts: 1 Thanks: 0 Curve fitting. Hoping someone can help me here. I've been fumbling around for ages with no success. I don't know how to post a picture which would probably help things a lot. I have 5 points and each point has different constraints. I need to find an equation (or equations) that will link the consecutive points with one smooth curve. The curve can only change curvature(inflect form +ve curvature to -ve curvatre) at points 2 and 4. Points 1 & 5 (2 constraints each) X,Y known Gradient = 0 Point 2 & 4 (2 constraints each) X known Curvature = 0 Point 3 (2 constraints) Y known Gradient = 0 That's 10 constraints. From what I believe I need a 10 variable equation to achieve it in a single equation or something like one 4th order polynomial and 2 cubic splines to find a solution. Is this right? Hope this is somewhat understandable. If someone can help me I will email excel files to show the track I was on.
 January 12th, 2008, 10:12 AM #2 Newbie   Joined: Jan 2008 Posts: 22 Thanks: 0 At first glance, I was going to say that you are seeking a spline; however, most spline routines I know about use just the (x,y) data pairs, and don't allow you to specify curvature or gradient at specific points. Incidentally, I am not clear about your terminology: I assume when you say Gradient=0 you mean the first derivative of the line is zero (i.e. - a horizontal line). However, when you say Curvature=0, what do you mean? Second derivative is horizontal? Are you looking for a theoretical solution? Or do you have real data pairs? You only have five data pairs, why not post them, so we can see what you are working with. As a guess, it sounds like a cosine curve: horizontal at 0, inflection point at 90 degrees, horizontal at 180 degrees, inflection point at 270 degrees, horizontal at 360 degrees. Tom

 Tags curve, fitting

 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post bottlerocket Applied Math 1 December 21st, 2012 05:45 AM colorless Probability and Statistics 6 October 4th, 2011 12:36 PM Stormer Algebra 2 September 11th, 2011 03:33 AM billymac00 Applied Math 0 October 13th, 2009 07:43 AM rainy cloud Applied Math 3 December 2nd, 2008 05:42 PM

 Contact - Home - Forums - Cryptocurrency Forum - Top