# Items tagged with differentialdifferential Tagged Items Feed

### how to do diff commands in Maple?...

November 02 2013
0 1

2. Give the Maple command(s) to compute \frac{\partial^8 f}{\partial^5 x \partial^3 y} for f(x, y) = e^{2x+ cos(y)}.

### how to get kalman form...

October 18 2013
1 0

The goal is to get Kalman Form

I am doing the example in page 707 of Partial Differential control theory Volume 2 by J.F.

when using Robertz Daniel's Ore and Involutive packages

with(Involutive):

with(OreModules):

Alg := DefineOreAlgebra(diff=[D,t...

### how to integrate by parts after multiply lambda(t)...

October 15 2013
0 3

Diff(x1(t),t) - x2(t) = 0;

Diff(x2(t),t) - x3(t) = 0;

Diff(x3(t),t) +3*x3(t) + 4*x2(t) + x1(t) = 2*Diff(u(t),t$2) + 5*Diff(u(t),t) + 7*u(t); multiply above system by test functions -lambda1(t),-lambda2(t),-lambda3(t) and integrate by part in order to find adjoint operator in the form x1 -> Diff(lambda1(t),t) - lambda3(t) = miu1(t) x2 -> Diff(lambda2(t),t) + lambda1(t) - 4*lambda3(t) = miu2(t) ### Differential Operator... September 30 2013 1 10 Can maple use a Differential Operator somehow in the following sense? Instead of expanding (D-p)^n where p is a constant and D the differential operator and n an integer and then in each term writing D^n(f) for some function can I just leave the expression as it is like (D-p)^n and acting on everything on the right? ### Total differentiate... July 22 2013 0 0 ### solving a differential equation... July 04 2013 0 4 Hi every body I want to solve a differential equation y'(t) = sqrt((f-1)/(t^f-t)) and get an answer in terms of ordinary function.is it possible. thanks ### Non-autonomous system of DE to autonomous one... June 17 2013 0 6 Hi, I'm searching for the third differential equation that will transform the following two equations non-autonomous system into a three equations autonomous one: diff(x(t),t)=-x(t)+2*(m*t+n)*y(t)-2*k*(m*t+n)2 diff(y(t),t)=-y(t)+k*m-(m*t+n)*((x(t)/2)-1) diff(z(t),t)= ... Regards, Johnny ### differential equation solutions... May 03 2013 3 2 Many times when I use dsolve to find the solution of an equation like x-y/y' = y , I get a term involving the LambertW function. However, the equation has homogeneous coefficients for dx and dy, so it can easily be solved by substituting y=u*x and separating the variables. The closed form solution of the above is x+y*ln(y)+c*y = 0 , but I cannot get that answer from Maple. Is there... ### terms identification... March 24 2013 1 2 Hello,  I'd like to identify terms before the differential terms (theta(t), diff(theta(t),t) ...) The following code with coeff function works for diff(theta(t), t, t)) but not for diff(theta(t), t) Here the code : eq1pp := R(t) = -(-sin(theta[0]+phi)*Isup-sin(theta[0]+phi)*L[fixe]^2*M[fixe]-sin(theta[0]+phi)*L[r]^2*M[r]-sin(theta[0]+phi)*L[sup]^2*M[sup]+cos(theta[0]+phi)*a*sin(phi)*L[fixe]*M[fixe]+cos(theta[0... ### How to split or directly plot a system of solved d... March 19 2013 1 2 Hi all, I am new to Maple and I have (possibly a simple) question. I'm solving 2 coupled differential equation, it all goes well, until I want to plot them. I have the output in the following form: sol = {w1(x) = [ -a*x^4+b*x^3-c*x]}, {w2(x) = [-d*x^4+e*x^3-f*x^2+gx-h]} My goal is now to plot the solution in 1 figure with w1(x) between x=0..100000 and w2(x) between x=100000..150000 I have searched on the web for a way to get the formula's of w1(x... ### How to interpolate roots for a curve expressed in ... February 15 2013 1 2 I'm solving a system of ordinary differential equations numerically, I used the dsolve(system,numeric) to do it. I have also plotted the solutions. Now I want to know where does this solution cross zero and use this value for later computations, is there a way to do it? This question is, as I think, equivalent to how to find the roots for a curve expressed in numerical arrays. Thank you! ### Solving system of differential equations with boun... February 14 2013 2 4 I know how to solve system of differential equations numerically, but now I want to know how to set a bound on the solutions. For example, if my system of DE is like this: dx/dt = x+y dy/dt = x-y , solve x and y in t. I can solve this without any restriction on x and y, now I need to know how to bound x and y, e.g. x can only fall in the interval [0,1] Thank you very much! ### Simplifying a vector expression with composite fun... February 13 2013 1 4 Hi all, I must confess I'm a perfect novice in Maple as I'm used to work with Matlab. I have a 3d differential equation, namely: = 0 The components of M should be of the form M_{i0} + dM_i(t) where M_{i0} is a constant and dM_i(t) a function of t, i = 1, 2, 3. And... ### Warning, expecting Range variable k blablabla... w... January 31 2013 2 23 I dont know what to do any further... I have some function containing HeunG as a function it is of the following form f(k)=argument(functions containing HeunG) - ln(2)*k now plotting this works... But when differentiating with respect to k and then plotting it gives me the following message: Warning, expecting only range variable k in expression (I*((1/2)^(1/2*I*k))^2*HeunG(3,-9/2+3/4*I*k-3/4*k^2,-1+1/2*I*k,-1/2+1/2*I*k,1/2,1+I*k,1/2... ### Differential equations solving and plotting... January 30 2013 0 3 Hi I have the differential equations: X := diff(F(t), t$2)+(10+8*sin(m*t)/(m*t))*F(t) = 0

I know that if it were X := diff(F(t), t\$2)+(W)*F(t) = 0, where W was a constant, then the solution would be the standard WKB sol, but with a time varying function in front this solution is no longer valid.

I know this can be done and would like some help in plotting F(t) against t and i sholud look an oscialltig curve where when sin(mt)=0 it...

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