Hi there

i'm trying to plot the phase portrait of a 2nd order ODE and i just cant get those damn arrows to come up. i've managed some solution curves but i'd like to see the phase portrait and maybe make an animation to see how it changes but i'll worry about that once i can get the arrows.

Dear all:

    I want to plot a function(say, z=x^2+y^2) on a nonsqure region(say, x^2+y^2<=1). What I did is to manually define a procedure so that it returns the function value if the sample point is inside the defined regioin, null otherwise.

region:=proc(x,y)
  if x^2 + y^2 <= 1 then
      return x^2+y^2;
   else
      return null;
   end if:
 
 end proc;

any info on the Jacobi iterative scheme

to get me started. please

consider the system

2x1 + x2     = 1

 x1 + 4x2 + x3 = -1

           x2 + 2x3=3

Find x using the Jacobi iterative scheme with x= (0,0,0)

My colleague at the university next week give a lecture where he tells about the Hardy-Ramanujan partition functions, the usual

notations are p(n) and q(n). He asked me, could I calculate by Maple a definite integral, because the answer was yes, then he

would say "by Maple".  I tried it in different ways, but no success. Could someone calculate it?

The exact result is  -1/2 ln (2 Pi) .

Hi. I have a couple of questions:

True or false? Why?

1. If f and g are differentiable and f(x) is greater than or equal to g(x) for a<x<b, then f ' (x) is greater than or equal to g ' (x) for a<x<b.

2. All continuous functions have antiderivatives.

Thanks!

hey guys.. ive been trying to get the root of the following equation.. but watever i do i am getting only the positive value.. and i have another equation which has 5 answers.. but only 1 is being shown.. can u help me out??

>f0:=x->x/(sqrt(x^2 + cos(x-1))):
>f1:=D(f0):
>f2:=D(f1):
>a:=fsolve(f1(x)=0,x);
                                a:=3.639062685
 

hi, how do i perform the following operation and simplfy?

(4a- 3ab + 2b) + [ (2a- 4b) - ab ]

We are contemplating using Maple TA.  I have been playing with a trial and it looks quite good.

If you read the Maplesoft advertising,  you get the impresion that a lot of Universities out there are using TA. 

On the other hand, the (rather variable quality) mapleapps question banks resource does not really contain a huge amount of material.

Hello all,

When I tried to plot with "semilogplot" command, I've found the ticks on the x-axis and the vertical grids do not line up. This is with Maple 10. Would somebody tell me if there is a way to line them up?

with(plots):

semilogplot(log[10](x), x=1..1000, gridlines=true);

Thank you.

Chin Li

Hi there.

I have two vectors:

x1:= [ ( 1+sqrt(1-4*a^2) )/(2*a) , ( 1+sqrt(1-4*a^2) )/2 ];

x2:= [ ( 1-sqrt(1-4*a^2) )/(2*a) , ( 1-sqrt(1-4*a^2) )/2 ];

I have the following questions to complete:

(2)Determine when x1 and x2 are both real

(3)Determine the largest interval I=(c,d) (with d>0) such that x1 and x2 are real and distinct.

The answers are obvious on paper, but I have to calculate this with Maple.  How do I go about this?

Thanks

Probably the easiest way to explain this is to show you what I want to do. I want to draw a contourplot which shows the contour lines going through the points [0,-1] and [3/4,-7/16] (these are the expression's stationary points).  The values of f at each of these points respectively are 1 and 101/128, so I have tried to display these contours, but when the graph comes up, the contour lines don't go through the point [3/4,-7/16], although they do go through [0,-1]. The code I'm trying to use is below.

f(x,y):=x^3-3*x*y+2*y^2-3*x+4*y+3;

Dear all,

I'm trying to duplicate by hand the variancecovariance matrix (and stanard error vector) of a simple LinearFit of data (2nd order function of form a + bx + cx^2), using the inverse of the curvature matrix as in Chapter 15 "Modeling of Data" of the Numerical Algorithms book 3rd Edition, or the paper by Keith H. burrell "Error analysis for parameters determined in nonlinwear least-squares fits", American journal of Physics, Vol. 58, No. 2, 160-164 (1990). Unfortunately, I cannot get the same answer, even with simple unweighted examples.

Hi,

I know it is possible to find a basis from a set of vectors using the 'basis' command but is it possible to find a basis from a set of matrices?

I'm trying to make it animate slowly without having to click the 'decrease frame rate' button. Does anyone know if there's something I can put in the code to make it do this?

Thanks