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

I need to find an example of a function of one variable that has an antiderivative that can be expressed very simply in terms of fuctions that a 1st-year calculus student would know, but int (command name in maple) can't find an antiderivative.

Hint: Start with the antiderivative F(x), and get f(x) by differentiating it and simplifying. You might try something involving a few square roots and logarithms or exponentials or trigonometric functions.

I need to find an example of a function of one variable that has an antiderivative that can be expressed very simply in terms of fuctions that a 1st-year calculus student would know, but int (command name in maple) can't find an antiderivative.

Hint: Start with the antiderivative F(x), and get f(x) by differentiating it and simplifying. You might try something involving a few square roots and logarithms or exponentials or trigonometric functions.

     I am trying to do a "radial" polar plot.  Yes, I know Maple can do polar plots, but their axes are always in the x-y direction.  I am looking for a polar plot that is round with the angle (theta)  labeled around the circle in degrees., and the value 'R' as the length from the center of the circle.  There should also be concentric circles marked with the distance from the center point so as to provide a scale for the R value.  So the grid looks like a round spiderweb.  Can Maple do this easily?  I looked all over the docum

Hi - I'm trying to solve a PDE using pdsolve() for the Graetz problem (heat transfer in a pipe). I can solve the PDE and get a general solution, but when I try to solve the equation with the boundary conditions, Maple thinks that the boundary conditions are new functions with the same name. Here is how I am doing it now: > heat := (1-z^2)*(diff(T(y, z), y)) = (diff(z*(diff(T(y, z), z)), z))/z; > cond := T(0, z) = 0, T(y, 1) = 1, diff(T(y, 0), z) = 0; > PDE := [heat, cond]; > sol := pdsolve(PDE, T(y, z)); This throws the error:

I need to find the square root of a large number, x (about 70 digits long).  If I use x^0.5, the answer is displayed in scientific notation and  is rounded.  How can I find this number exactly?

I have 2 functions, f(x) and g(x) both continous on [a,b] (a known interval). For which value of C ε [a,b] the area under f(x) and g(x) is minimal?

I know f(x) and g(x).

I have 2 functions, f(x) and g(x) both continous on [a,b] (a known interval). For which value of C ε [a,b] the area under f(x) and g(x) is minimal?

I know f(x) and g(x).

In implicitplot, to insure the accuracy  of a curve, I usually increase the number of points (numpoints=*** ) or increase the number of grids ( grid=[***,***] ). Both can improve the quality of the curve. And sometimes one works better than the other. But I don't quite understand the relationship between the two options , and which is more effective and more economical. Thanks.

I want to plot  the astroid by the following code, but only the part in the first quadrant appears. I don't know that is wrong and how to solve the problem. Thanks.

with(plots):
a:=1:
implicitplot(x^(2/3)+y^(2/3)=a^(2/3),x=-a..a,y=-a..a);

Hello

I am running NLPSolve within a loop over some values of parameters. For one of the parameter values, the NLPSolve gives me

Error, (in Optimization:-NLPSolve) no improved point could be found
 

and exits the loop. How do I change this behaviour? I would like the loop to continue for other parameters.

I have tried interface(errorbreak=0) interface(errorcursor=false) but this didn't work.

Can anyone help please.

Thank you, Best Regards

Jan Zapal

 

 

Does Maple have a command for plotting  regular polygons? How can I plot a regular polygon insrcibed in a circle? Thanks.

By the way, I read from a book that an N-polygon can be plotted as follows. But I wonder if this is the easiest way.

with(plots):with(plottools):
R:=1:
C:=circle([0,0],R,color=red,thickness=3):
N:=7:
a:=I*(2*Pi*i/N+Pi/2):t:=R*exp(a):
P:=polygonplot([[seq([Re(t),Im(t)],i=1..N)]],color=blue):
display(C,P);