Hi there, Here is my problem : I'm trying to represent ( and animate ) the surface of a vibrating circular drum using plot3d. Let O be the center of the drum, the function "u" I found gives the height (z) of a point on the drum located at a distance r from O at t ( time ) in cylindrical coordinates ( u does not depend on theta). So what I'm basically trying to do is to plot the surface given by the equation z = u(r,t). So far I've failed to do so using plot3d. Could someone here help me with this ? Any help will be greatly appreciated ! Thank you. Tiilt

I have got two columns of data X and Y. if i know the data would possibly fit a function with form : y=ax^n+bx+c, how could i extract the values of a, b and n? Also, how to get the R squared value for the curve fitting.

I use D[ ] to get partial derivatives,

as follows,I donot know is it right?

w := proc (x, y) options operator, arrow; A*(x^4-2*L*x^3+L^3*x)*sin(n*y/R) end proc

t4 := (D[`$`(1, 4)](w))(x, y)+2*(D[`$`(1, 2), `$`(2, 2)](w))(x, y)+(D[`$`(2, 4)](w))(x, y)

If we have three coins. Then the probability of getting three heads or three tails is:

0.5^3 + 0.5^3 = 0.25

Now, what is the probability of getting three heads or three tails when the three
coins are correlated with correlation coefficient p ??

i want someone to help me with this intergration w := (int(K/(y-y1), y = -s .. s))/(4*Pi) he want to know if y1 is between s and -s ,while y1 really exist between s and -s thanks

a:=["34mt5","tru532","64E22N"]

I thought this command worked on Lists.

Select(HasDigit,a)
    Error, (in StringTools:-Select) second argument must be a string

So then I thought maybe map might work

map(HasDigit,b)
     [true,true,true]

okay closer. 

Select(map(HasDigit, c), c)
     Error, (in StringTools:-Select) second argument must be a string

Can't figure out how to get around that string problem

I noticed that if I use add instead on using an integral int I dont get the same value. why ??

restart:
E := 7:   p := .5:
add(p^n*2^(n-1), n = 1 .. E)-p^E*add(2^(n-1), n = 1 .. E);
evalf(int(p^n*2^(n-1), n = 1 .. E)-p^E*(int(2^(n-1), n = 1 .. E)), 5);
 
                                  2.5078

Dear reader,

For a concept evaluation I need a system of 13 equations to be solved. Not necesserarily explicitliy, it would be sufficient for me just to see dependencies between variables. However either me or Maple or both are incapable of doing so. I am using Maple 13 by the way.

Hi, I'm having trouble getting Maple to solve the following simple inequality: H:=sqrt(1-0.3*sin(f)^2), solve(H>.9).  I get no solutions regarless of assumptions ect.  However, solve(H^2>0.9) works fine.  Anyone know whats going on?

thanks

okay, so I was asked this question

Hi,

Assume I have an eqn:=diff(x(t),t)+diff(y(t),t,t)+x(t)=0(It is just an example) for example, how can I find in which order variables are apearing here in this eqns?

for example I can give this eqn and result for x would be 1 and for y would be 2.

What is Maple command for that?

Thanks in advance,

Bye

 

 

I have two lists in Maple that I would like to join into a single list based on the values in a common field.  The best tool for such an operation is a relational database management system (RDBMS) where I would use SQL JOIN syntax.  The R program for statistics has an internal command, "merge" which can perform this operation on data frames [http://stat.ethz.ch/R-manual/R-patched/library/base/html/merge.html].  I would like an analogous operation in Maple as a convenient alternative to turning to a full RDBMS.  Does Maple offer such a command?

I have an application for wave temperature propagation in soil: with (plots); > u(x,t):=A*exp(-sqrt(w/(2*a^(2)))*x)*cos(-sqrt(w/(2*a^(2)))*x+w*t); > w:=10; > A:=4; > a:= 4*10^(-3); >plot3d(u(x, t), x = 0 .. 10, t = 0 .. 10); It is for x = 0. How can I do for x>0? Thanks, Raluca

I have an application for wave temperature propagation in soil: with (plots); > u(x,t):=A*exp(-sqrt(w/(2*a^(2)))*x)*cos(-sqrt(w/(2*a^(2)))*x+w*t); > w:=10; > A:=4; > a:= 4*10^(-3); >plot3d(u(x, t), x = 0 .. 10, t = 0 .. 10); It is for x = 0. How can I do for x>0? Thanks, Raluca