## 189 Reputation

18 years, 210 days

## 3D fit question...

Maple

I have a set of 3D data points that I'm trying to fit to a f(x,y) mocel and I do not know how to fit the data to the model. I am using the statement

g:=Fit(a+b.x+c.y+d.x^2+e.x.y+f.y^2, x,y,z,[x,y]);

where x,y are the independent vairables and z the dependent variable that I'm trying to fit.

My problem is that I have the error message

## License file no longer valid...

Maple

After updating my PC to Windows XP SP3 Maple no longer runs. A box with the message: "

Invalid or missing license file

License server does not support this feature

Feature: Maple 11

FLEXlm error:-18,147

appears and Maple does not start. Maple worked fine before SP3 update.

Does anybody have the same problem? Any idea about how to fix this?.

## Invalid specification of initial conditi...

I have the following diff equation with IC that I am trying to solve but I always get the "invalid specification of initial conditions" message. Here is the definition of the function and IC:

alpha:=0.024:g:=9.81

var:={x(t),z(t),dx(t),dz(t)}:

eqn:=diff(x(t),t)=dx(t),diff(dx(t),t)=-0.51*alpha*dx(t)*v(t),diff(z(t),t)=dz(t),diff(dz(t),t)=-g-0.51*alpha*dz(t)*v0(t):

initcond:=x(0)=0,z(0)=h,dx(0)=v0*cost(theta),dz(0)=v0*sin(theta):

h:=1,v0:=25,theta:=15,w:=20:eta:=1:

sol:=dsolve({eqn,initcond},var,numeric);

## Error, invalid loop...

Maple

How do I enter a nested for, if loops in Maple in multiple lines. I can enter the loops in multiple lines with no error message, while in the classical worksheet. But entering the same loop sequence in standard worksheet gives me "error, invalid loop" message after entering the first

for i from 1 to 100 do

statement . The error does not ocurr if I enter the for, if statements in one single line

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