Hello,

I was wondering what the easiest way to calculate the derivative of a matrix is?

So far I am trying:

> with(LinearAlgebra);
with(VectorCalculus);
> A := Matrix(2, 2, {(1, 1) = 1, (1, 2) = x^2, (2, 1) = 4*x^7, (2, 2) = x^3});
                           Matrix(%id = 163320844)
> B := D(A);
 

hi.

when i want to modify a parameter it's easy:

test1 := proc(x::uneval)
    x:=eval(x)+1;
    NULL;
end proc;

x:=5;
test1(x);
x;

ok x is now 6

How to do that with lists of names ?
ie writing a procedure test2 so that I can do that:

x:=10;
y:=20;
test2([x,y]);
x,y;
      11,21

thank you

 

Dear all:

   I wonder if there is any function in Maple checking whether a given function is (m-th) differentiable or continuous? 

 

Thanks,

Peter

Hi,

I have the following set of ODE:

sys := diff(U(t), t) = Itot/C-U(t)/(R*C), diff(U(t), t) = (Itot-I1(t))/C, diff(U(t), t) = I2(t)/C

The general solution is easily obtained by:

sol1 := dsolve({sys})

SOLUTION: sol1:={U(t)=Itot R+(e)^((-(t)/(R C))) _C1,I2(t)=-((e)^((-(t)/(R C))) _C1)/(R),I1(t)=(Itot R+(e)^((-(t)/(R C))) _C1)/(R)}

However, I cannot get the solution for initial conditions. In fact, we only need one initial condition, to solve for _C1:

IC:=U(0)=0  #Alternatively: I1(0)=0 or I2(0)=Itot.

Let w =f(z) = sum of z^(k+a) / (k + a)

where k= 0 to infinity and a is a nonzero parameter.

I need to find the inverse of this series, z = g(w). The powseries examples in Maple Help don't help. They don't work on my example, with a symbolic variable, a, stuck in there.  I hope that if I see about 7 or 8 terms of the inversion, I will get the general pattern.  I have tried to compute the inverse directly from the Lagrange Inversion Formula, but the complexity always grows too quickly for me to complete the solution, no matter which shortcut I try to take.

I have an equation which i have differentiated twice and evaluated at eta=1.
F''(eta)=-3*eta+(3*eta^5/20-9*eta/140)*R+(eta^9/840-3*eta^7/140+9*eta^5/1400)*R^2+...
evaluated at 1 we get
F''(1)=-1+3*R/35-394*R^2/40425+4924*R^3/6131125-43969148*R^4/980274920625+...
This equation is derived by an iteration process. Each time it is iterated we add an extra term where the power of R increases by 1.
I want to write R in powers of (F''(1)+3).
How would i go about doing this with maple?
If it is easier to write

Write a procedure

input:a polygon and a linear transformation

output :applying the transformation to the polygon
 

Find the coordinates of the linear transformation that would have  the a larger square to the pink (smaller) square.Apply the transformation to the blue square.
 

please help with this, thnaks

Hello, it's been awhile since I've used maple and I'm a little stuck here.

I'm basically trying to model charging of a capacitor with a load dependant voltage source. Capacitor voltage depends on source voltage but source voltage depends on capacitor voltage, classic ode problem. Now I can define the entire ode in one statement and then solve but I'd like to define the components that the ode is made of and then solve for d(f(x))/dx and then dsolve. When I try to build an ode with multiple statements however, I get a 'too many levels of resursion' error.

Use a procedure that takes as input a positive integer and two real numbers a and b
and produces as output  a polygon centered at (a, b). Base on the procedure,  obtain a list of twenty decagons centered in (0, 0), (1, 1), ..(20, 20)

(I have no hint,please help, thanks)

hi, i am trying to show that the sum of (1/2 + 2/3 + 3/4 + 4/5 + ... +n*(n+1)+ ...) can be approximated by the following: sum(1/(exp(1))^(1/n), n = 1 .. infinity). e.g. > sum(1/exp(1/n), n = 1 .. 10); print(1/exp(1)+1/exp(1/2)+1/exp(1/3)+1/exp(1/4)+1/exp(1/5)+1/exp(1/6)+1/exp(1/7)+1/exp(1/8)+1/exp(1/9)+1/exp(1/10)); 1 1 1 1 1 1 1 1 1 ------ + ------ + ------ + ------ + ------ + ------ + ------ + ------ + ------ exp(1) /1\ /1\ /1\ /1\ /1\ /1\ /1\ /1\

I have tried the Physics package. First of all, how can I define a non-ortogonal basis (using kets)? Suppose I have a basis formed by linearly independt vectors. How to set them non-ortogonal?

Using plot3d I can obtain a plot of a function u:=f(x,y). Then I rotate the plot and find the view that I want by trial and error. However, If I run the plot again with different parameters, I have to again find the view I want by trial and error. Setting the plot3d orientation option by trial and error to achieve the required view is very tedious. My question is: Once I have found the view I like, is it possible to then obtain the orientation data so that it can be used in subsequent calls to plot3d? Any help appreciated.

Hi there, in this post http://www.mapleprimes.com/forum/howplot1 I asked one plotting question when Y[1] and Y[2] are independent what if they are not independnt? say I have f( y1, y2) for Y[1] in [a,b] and Y[2] in[c,d] then I have U[1] = f ( Y[1], Y[2] ) and U[2] f ( Y[1], Y[2] ) (different functions of Y[1] and Y[2]) How do I plot the mapping for U[1] and U[2]? to determine the range for u1 and u2? Thanks Casper =============================

Hi everyone!

I'm stuck with a problem, and I thought I might get some help here. Would be greatly appreciated. Anyway, here goes:

For a given function of two variables, say g(x,y), we can produce a 2d-contourplot (for example using the contourplot-command). No that's all swell as long as we actually have a closed expression for our function g (like, for example, sin(x^2 + y)).