Recent content by androsnich

Hello, I am repairing a 4' x 10' septic tank built with 2"x12" rough redwood. I have some concerns about rotting, sealing the tank, and building an accessable cover. All of the top two courses of of 2x12 are rotting; some of the bottom courses also. The floor is in good shape except as noted...

Hello, How do I get rid of "dry" septic tank sludge? I recently dug out the sludge from an "out of use" septic tank. The sludge is the consistency of moist dirt. It is black, sticky and greasy. I have about 2 cu yds (800 pounds). Can I use it as land fill and put it back in the soil? Do I...

Hello, I am repairing a 4' x 10' septic tank built with 2"x12" rough redwood. I have some concerns about rotting, sealing the tank, and building an accessable cover. All of the top two courses of of 2x12 are rotting; some of the bottom courses also. The floor is in good shape except as noted...

Gearguru, I too have bogged down trying to solve the fourth order polynomial equations. I would be interested in seeing your friends analysis. I'm at american_flyer(at)juno.com . Thanks, Harry

kapitan, As I have been thinking about solving quartics, I have considered the solution does not have to be exact. Some of the accuracy criteria I have thought of are: 1) The accuracy could be expressed as the point-ellipse distance +/- some absolute tollerance. 2) Or the accuracy could be...

I forgot to say I am initially looking for a closed form solution...non-iterative. And I am programming the solution using Fortran (or C). I also have to do this about 1.5 million times or so. (IFR: I like your iterative method because it is very straight forward, but may be time consuming.) Harry

I forgot to say, I will be solving this in Fortran (or some other language). I am looking for a closed form solution. TheTick: You give me an interesting idea - rolling a circle over the ellipse until it intersects. I have tried calculating the formula for the normal line (to the...

Shortest Distance to Ellipse from Point, Or: What is the Line Perpendicular to the Ellipse? What is a good method to determine the shortest distance from a point to an Ellipse? This is similar to finding the line through a given point that is perpendicular to an ellipse. To make it simple...

Shortest Distance to Ellipse from Point, Or: What is the Line Perpendicular to the Ellipse? What is a good method to determine the shortest distance from a point to an Ellipse? This is similar to finding the line through a given point that is perpendicular to an ellipse. To make it simple...

Shortest Distance to Ellipse from Point, Or: What is the Line Perpendicular to the Ellipse? What is a good method to determine the shortest distance from a point to an Ellipse? This is similar to finding the line through a given point that is perpendicular to an ellipse. To make it simple...

Greg When you say use an analytical method for 3 points, do you mean to assume it is a parabolic curve and just plug the values into something like y = ax^2 + bx + c ? I say this because I don't know the I don't know the form of the curve. I think (for data points where x is close to the...

How can I do a simple non linear least squares regression on a few data points inorder to find the inflection point? The data resembles a second order polynomial, a parabola. I have about 3-4 points and need only an approxmate answer. I figure I can do a simple polymonial least squrares...