I'm working with a PDE system, I want to bring it from the conservative(or divergent) to not-conservative form. So I have to do some derivatives. I'm working in vectorial form.

I have this expression:

(a*x^2+b*x*sin(y)+c*sin(y))^2+(a*sin(x)^2+b*x)^3

I have to rewrite this as a multipolynomial in the variables x and sin(y).

I'm trying this:

expand((a*x^2+b*x*sin(y)+c*sin(y))^2+(a*sin(x)^2+b*x)^3, x,sin(y));

but i get the same result as expand without the 2 variables at the end.

am i doing it right?

Thanks in advance!

When I integrate the partial derivative of v(x,y) with respect to y from y = 0 to y = Y using

 

int(diff(v(x,y),y), y=0..Y)

 

Maple simple echos the integral in typeset format. I expected to get

 

v(x,Y) - v(x,0)

 

What am I missing here? This integral comes from integrating the 2D continuity equation in boundary layer. Any help would be greatly appreciated.

 

Thanks,

 

Neill Smith

Hi guys. I'm trying to do something like this: add(add(f[m-k,k], k=0..m), m=1..d); and I want to get Maple to print the coefficients i.e. f[1,0]+f[0,1]+f[2,0]+f[1,1]+f[0,2] etc. I guess what I'm stuck on is how the Array for f should be defined? Any ideas? Thanks, Tom

I need help solving the following integral with Maple

int(erfc((R+3*t)/(6*t^1/2)),t=0..1)

I have a new one :) I need to find the critical points and tell their nature of a 3 variable function. It's a new thing for me and i'm not sure if i did it ok, here's what i have tried:

g := 1-2*x+3*x^2-x*y+x*z-z^2+4*z+y^2+2*y*z;

ex := extrema(g, {}, {x, y, z}, 't'); - stores the extreme value of f in ex

evalf(ex); - displays the extreme value in decimal

t; - contains the critical points of f

evalf(t); - displays the critical points in decimal

Here's what i have to do. i have a system formed of 3 equations, and i have to find the solutions ( there may be only one ), and the make sinus out of it evaluating it with 5 digits.

I am finding problems with plot first:

I am trying to find out all the real solutions of a system of 2 eqns and i just can't figure it out. Here's what i'm trying:

>eqn1:=x+y=9;

eqn2:=x+y-sin(x*y)=7;

solve({eqn1,eqn2})

 

After i hit enter, i get this warning:

 

Warning, solutions may have been lost

 

I'm completely lost !:(

 

Dear all:

   I assume this is an easy question, but I simply couldn't find an answer: How to sample from a multivariate normal distribution give a mean M and covariance matrix Ccov? The statistics package seems to only contain 1-d distributions.

Thanks a lot,

Peter

plot (arccos(cos(x)),x);

At x=0, arccos(cos(x)) should be shown on the graph at (0,0),  As I zoom in I find that Maple draws it at closer to the point (.01,-.01) not at all at (0,0)

How do I create 3D polygone by a list of points using maple.?

I convert following differential equation to the s domain: restart: with(inttrans): > DV:=diff(y(t),t$2)+3*diff(y(t),t)+2*y(t)=diff(x(t),t): > x:=t->10*exp(-3*t): > laplace(DV,t,s); As solution I get: s^2*laplace(y(t),t,s)-D(y)(0)-s*y(0)+3*s*laplace(y(t),t,s)-3*y(0)+2*laplace(y(t),t,s) = -30/(s+3) It's not really a Maple problem but I don't understand why the right hand side of the equation is -30/(s+3) . When I transform the right hand side of the differential equation manual to the laplace domain I would do it as: diff(x(t),t) = s*X(s) = s * 10 /(s+3)

Is there a way to solve following equation in maple? I have already tryied intsolve and dsolve without succes. DV:=diff(y(t),t)+5*int(cos(t-tau)*y(tau),tau=0..t)=10; Thank you, Pieter

An annoying feature of Maple is that if it crashes (all too often) & you have not given your worksheet a name, the file is lost despite having activated Auto-Save.

1)   Is the previous statement correct for Maple 9.5?

2)   If so, has this bug been corrected in later versions?

Alla