## Problem with SparseIterative?...

Hello, everyone! I have a very nice, very sparse linear system (only containing 1s and -1s, with at most 2 entries per column). Thus, I immediately thought to take advantage the SparseIterative (or SparseDirect) methods associated with LinearAlgebra,LinearSolve, but alas, it isn't quite working. This is what I loosely do: gen_linear_system := proc(... some parameters ...) ... ls_m := Matrix(len, total_var, datatype='integer[1]', storage='sparse'); ... (fill matrix with appropriate 1s and -1s) return ls_m; end proc; solve_linear_system := proc(system_matrix::Matrix)

## fourier series...

hi! I want to do maplet application that fourier series calculate given funtions how do I? thank you...

Thanks

## How to plot the intersect line of two implicit fun...

Hi, Folks: I have two implicit functions (hyperboloid)： sqrt((x-28)^2+(y-2)^2+(z-2)^2)-sqrt((x-20)^2+(y+20)^2+(z-6)^2) = 2 sqrt((x+15)^2+(y-2)^2+(z-2)^2)-sqrt((x-20)^2+(y+20)^2+(z-6)^2) = 10 I am able to plot these two functions through display3d, but right now I want to plot the intersection line. Anybody has comments or suggestions? Thanks a lot, James

## first derivative...

Hi, How do i make maple to write a fist derivative with respect to time ie i want maple to show y' in the output.

## Discontinuous 3D-plot...

Hi. I'm trying to make a 3D-plot of a function f(x,y) that is discontinuous but can not figure out how to do it. I'm new to Maple but I found that there's an option discont=true for 2D-plots. Something similar for 3D? Cheers

## I want clear just some variable Not all of them???...

Hi, I want clear some variable Not all of them in my program(restart command clear all of them), is it possible in Maple to do that?Tanx.

## Root Finding...

I have a problem: I have an ODE, dT/dy, that depends on y and k, but k itself depends on rho and T. The only problem is rho cannot be obtained analytically--it's a complicated function. However, I can use a rootfinding algorithm,(fsolve), to determine rho at given values of y, thereby making my ODE solvable. I want to use dsolve to numerically solve this ode. The problem is I can't seem to be able to input the fsolve equation as an argument to the dsolve command. It keeps telling me : Error in fsolve, y is not solved for. But my intention is to use y to solve for T and rho in dsolve. If anyone has any idea I would greatly appreciate it.

## Finding turning point, intersection of functions...

Hi people, I have two questions and help on any of them would be greatly appreciated. 1. My first question is how would i find the point(s) where the two equations intersect? eg. 4*(x-1)^2+(y-2)^2 = 5; x^2+4*y^2 = 1; 2. My second question is how do i find the turning points of a function? eg. x*cos(x^2)/(1+x^2) Again any help is really appreciated. Thanks in advance.

Hey guys Does anyone know how to include an fsolve command incorporated into the dsolve command? In other words, as dsolve iterates the runge kutta procedure, it uses the inital values to use fsolve which would then be used over again in the rk procedure.. Thanks B-rad

## question about fractional form / evaluating cfrac ...

Where can I find a description for the various variants of numtheory:-cfrac, which goes more into details than the online help? For example one can guess how an approximating sum can be obtained from numtheory:-cfrac((a+x)^k, x, 7, 'diag', 'simregular', 'quotients'); but I prefer to cross-check against a confirmed formula instead of guessing. If somebody would be so kind to point me to some source to look at ... or even knows it already ...: how does one evaluate the above list to get a value? -- edited to add: I mean a way which can be compiled and without running through

## Does it surprise you.....

Does it surprise anyone that Maple can't run a loop from i=10^8 to i=10^9 ? Or is my computer just too slow? Thanks Brandon