## Express simultaneous equations in matrix form...

Hi, I am trying to create a sheet to show the derivation of 2nd and 4th-order function derivatives as part of a 5-point finite difference scheme for a 1-D model (a continuous beam on an irregular foundation). I have isolated 2 simultaneous equations by using Taylor polynomials and would like to cast these in matrix form and then solve for each of the D-operators symbolically. Is there a simple way to do this or do I have to work with the ops manually? thanks for any help, Neil

## sqrt(4)=?...

I have difficulties understanding why exactly Maple finds the question difficult to answer. First attempt: assume(a>0); a:=sqrt(b^2); eval(a, b=2); (1/2) / 2\ a := \b / (1/2) 4 I suppose the problem is that after the assignment Maple forgets the assumption a>0(?). Is there a way to make _real_ assumptions on variables, which Maple will not forget and possibly warn me if I try to violate?

## ODEs with pertuabutions at specific time points....

Dear All, I have two odes, dX/dt = -X(t)*Y(t) and dY(t)/dt = X(t)*Y(t) I can solve these numerically using the following code: ```eq_1:=diff(X(t), t)=-X(t)*Y(t); eq_2:=diff(Y(t),t)=X(t)*Y(t); IC:={eq_1, eq_2,X(0)=10,Y(0)=1}; F:=dsolve(IC, {X(t),Y(t)},type=numeric, method=rosenbrock); h := theta->eval(X(t),F(theta)); h(1);``` However, I would like to add perturbations at specific time points. For example, at t=10, set X=5, or at t=15, Y=0. How should I do this in maple? Note: my actual situation involves a 100 odes. Thanks, Colin

## fibonacci polis...

How can I write a recursive algorithm on maple wich gives me the fibonacci polinomies knowing that: F1(x) = 1 F2(x) = x Fn+1(x) = xFn(x) + Fn−1(x), n = 2, 3, ... i think it's easy but still can't do it...if anyone knows help me please

## frustration with factors in a polynomial...

I subs (a^2=4b, expression) and get (1+b)*x^2+a*(1+b)*x+b(b-1)+2*b visually, (b+1) is a factor of the polynomial but the machine refuse to recognise this, I tried /(b+1), collect, expand and simplify and all failed. This is quite a frustration to new user who just want to get things done quickly!

## # of variables in a polynomial?...

Hello, everyone! Given a polynomial: f := x^2*y + 10*z*w + 2*a*t I would like to know how many different variables appear in f. Is there a command I can use to do this? My actual polynomial is more like: f := x[1]^2*x[2] + x[127]*x[3] + ... Any help would be appreciated! Thank you very much, and happy holidays! Best, Susan

## Poisson Distribution Values in Probability/Statist...

I am new to the Maple v.11 world and trying to figure out how to do things. I'm getting lost with the instructions in the help screens. Here is the problem: Can somebody show me how to enter this into Maple. Find the probability of an observation falling within one standard deviation of the mean. A Poisson distribution with [lambda]=16. Two other questions are normal distribution with mean=20, and a gamma distribution with [alpha]=4 and [theta]=5. I'm sure that if I can figure out one of the problems, I can figure out the others. Somebody please show me how to enter the problem

## How can I..?...

Hi I have data I want to fit it I do not know the model function I know only that the relation between X and Y is non-linear and there is six parameters I want to know their values from the fitting.can I do this using Maple or it is impossible. this is Maple work sheet: Download 7089_X0165.txt
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## Multiple function calls within Maple Addin...

Is it possible to execute an fsolve() for the equation as given below? I have not been able to get it to work thus far. Thank you for your support. Excel cell formula: =Maple("fsolve(2*(2*EllipticE(&1)-EllipticE(sin(beta),&1)-EllipticK(&1))+2*EllipticF(sin(beta),&1)=tan(beta)*sqrt(1-&1^2*sin(beta)^2),beta);",I14)

## Does Maple have a built in function that will cacl...

I have looked around and can't seem to find anything. Something simple that would provide the number of days eleapsed between two date/times. This comes in handy for radioactive source decay calculations. Thanks, GL

## finit sum of variables...

I just started using maple I want to count such thing: ( sum {from j=1 to k} ( x_j - b ) - sum{ from i=1 to n}( y_i - b) )^2 It's a part of longer equation. As a result I need a formula not a value. It is possible to count it with a build-in maple command? I have problems with writing the sum. If not could someone give me a tip how to write a program?

## Calculating the domain and range of a function?...

Hi, I need to find the domain and range for x=(1/5)*e^(y/2). How do I do that in Maple? Thanks!