When integrating 1/x as int(1/x,x) the answer is ln(x) while it should be ln(abs(x)). How does one fixes this mistake?

maple_error.doc

Hi friends,

I have windows 7, 64 bits, and I upgraded my maple to 64-bits version as well (Maple 13.02). But I wonder why in the task manager of windows, maple is still tagged as a 32 bits application (e.g. "maple.exe *32"  and  "mserver.exe *32")? In fact, I think the reason that I cannot run one my maple projects, which needs more than 2GB RAM, comes from this issue. Could you help me resolve the problem?

Thank you!

I've been given the relationship:

R*sqrt(sigma)-1-(1)/(4)*(l-(2*kappa*R^2)/(R*sqrt(sigma)))/(1+coth(R*sqrt(sigma)))-kappa*R^2/6+m/(2*R), for the particular case where m=l=0, and where

R=exp[(kappa*(R^2))/6]. On a sketch of R vs kappa, apparently sigma >0 on the lower branch, but there should be some sigma < 0 on the upper branch.

To attempt to solve this whole problem, I use the following commands:

restart;with(plots):

Hello

I have the following nonlinear differential equation:

deq := (diff(y(x), x, x))*y(x)-1+x*y(x)^2 = cos(x);

I solved it numerically:

sol := dsolve({deq, y(0) = 1, (D(y))(0) = 1}, numeric);

ysol := proc (x) options operator, arrow; rhs(sol(x)[2]) end proc;

plot('ysol(x)', x = 0 .. 5);

but I would like to substitute it to the left side of deq and plot it, to be sure that it's plot is the same as cos(x).

Hi everyone, here we are again with more serius issues this time.

I have a system of DE to solve. My system is made of coupled 3 PDE`s with 1 ODE. My problem is that the computation is aborted due failure at memory allocation, here is the message:

"Error, (in factor/nexteval) Cannot Allocate Memory (size=151060480)"

I`ve checked the kernelopts about datalimit and its already infinity. My computer is a Turion x2 with 4Gb of Ram (system...

Hi

I want to solve this

2010.pdf 

I have a family of functions characterized by

f:=x^2+b*x+b*3;

I plotted some of them:

graph1:=x->subs(b=0,f):
graph2:=x->subs(b=2,f):
graph3:=x->subs(b=4,f):
plot([graph1(x),graph2(x),graph3(x)],x=-10..3,y=-5..15);

And now I want to draw a line through all maxima into the same diagram. The maxima have the coordinates (-1/2*b | -1/4*b^2+3*b). I managed to create a pointplot:

I need to calculate the following conditional expectation

with the marginal density

and

being the density function of a normal N(mu, sigma) distributed random variable

I tried to solve this problem. 

It is a Maple TA question, but I get my solution wrong.

***********************

Question:

There is given a linear equation system consisting of two equations with four unknowns.

I want to differentiate the following (example) sum with respect to each variable.

foo:=sum(x[i]^2,i=1..3);

By hand I solved it like that:

g1:=diff(foo,x[1])=0;
g2:=diff(foo,x[2])=0;
g3:=diff(foo,x[3])=0;
solve({g1,g2,g3}, [x[1], x[2], x[3]]);

This works for i=1..3 but later I want to have it approach infinity. I don't have that much time to do it by hand -- what's a cleaner solution?

I would like to express a matrix in a neat(er) form.  For example, both matrices;

Matrix([[1/4, 1/2], [1/2, 1/4]]);

(1/2)*Matrix([[1/2, 1],[1, 1/2]]);

return the same thing.  I would like maple to print the latter with the factor 1/2 preceding the matrix for better clarity.  Is there a simple command that will do this?

Cheers in advance.

Rob

Are there a way to this in calculate this in Maple?

I have a system of linear equations, with two equations:

x[1]+x[2]+2*x[3] = -5

x[1]+x[2]-2*x[3] = 3

a) Find one solution to this nonhomogeneous equationsystem? The answer need to be in vector form.

b) Find the "complete" solution to the homogeneous equationsystem? The answer need to be in para mite based vector form.

How do I find find an invertible matrix P and the diagonal matrix D such that A=PDP. Are there a Maple command that can do that. I need it to an Maple T.A. exam.

A= 

(−3 0 6)
(0 -3 −6)
(0 0 3) 

Hi, everyone,

I am dealing with a simplified model of my real problem. Here is the function definition

f:=(x,lambda)->min(x lambda,0)

I can plot this function in plot3d:

plot3d(f(x,lambda),x=-2..2,lambda=-2..2, axes=boxed)

but if I try to plot the derivitive of this function w.r.t. lambda (which is a discontinuous function) by:

plot3d(diff(f(x,lambda),lambda),x=-2..2,lambda=-2..2, axes=boxed)

I get error message: Error, (in PiecewiseTools:-Convert...