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| I would like to isolate the coefficients from the solution of this ODE, into a list: sol = DSolve[{y'''[x] + y''[x] + y[x] == 0, y'''[0] == 1, y''[0] ==1, y'[0] == 0}, y[x], x] soln= TrigToExp[sol]; Cases[soln, a_... |
| Hi, I am trying to go from a set of points to a piecewise function. I use the following command, but I get only one large step , in the step-wise function. points = {{1004.9591023489934`, 213.55957424496637`}, {998.3619966442955`,... |
| Hi, I am trying to set up a code to plot a streamplot from the results from a SIR model. The problem to solve is **r′=F(r)** where r=(x,y) and F(x,y)=(−b*x*y/n,b*x*y/n−k*y) and where b=3.3925; k=2.95; n=157759; How can I set up... |
| Hi, I have the given command sol = Flatten[DSolve[y'[x] == y[x]^3/x^3 + y[x]/x + 1, y[x], x]] which yields the solution Solve[ArcTan[(-1 + (2 y[x])/x)/Sqrt[3]]/Sqrt[3] + 1/3 Log[1 + y[x]/x] - 1/6 Log[1 - y[x]/x + y[x]^2/x^2]... |
| c=3*10^8 T=0 h=1.0545718* 10^(-34) u={1,0,0,T}/Norm[{1,0,0,T}] v={0,1,0,T}/Norm[{0,1,0,T}] a={0,1,0,T} ⋅{0,0,c,T} b={0,0,1,T} ⋅{0,c,0,T} d= {0,0,1,T} ⋅{c,0,0,T} pde =I*h^2*(u⋅a-u⋅b)*D[psi[x, y,z,t],x]... |
| Hello, I would like to solve the following PDE for Psi(x,y,z,t) ![enter image description here][1] [1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=Screenshotfrom2021-08-2615-21-55.png&userId=967554 where alpha,... |
| Hi, I am trying to write up a ladder function, I use Piecewise: f[x]=Piecewise{{1.5, {-6 |
| Hello, I have a a polar function given by: u[r_, phi_, n_] := Piecewise[{{BesselJ[1.5 r, n]*Exp[I n phi], 0 1}}] u0[r_, phi_, k_] := Sum[I^(-n) BesselJ[n, r] Exp[I n phi], {k, -5, 5}]; u1[r_, phi_, n_] := ... |
| Hello, I struggle in finding a way to plot the following polar functions in 3D. Can anyone help? Here are the two functions, u and u_1: n=5 u1[r_, phi_] = Sum[I^(-n) BesselJ[n, r] Exp[I n phi], {n, -5, 5}] + ... |
| Hi, I would like to convert the given function. uA[r_, phi_] := {BesselJ[1.5 r, 5]*Exp[I 5 phi], 0 "Cartesian", uA[r, phi], {r, phi} -> {x, y}] I get something weird, which does not look like a function. It seems the boundary part 0 |