Tag Info

New answers tagged


The reason is, that the nicely formatted subscripts in the frontend looking like $c_f$ are no "real" variables, but are represented as Subscript[c,f]. You can see that, if you use FullForm on one of those subscript-lookalikes. Therefore, your code does end up trying to create the derivative of the Mathematica-function Subscript, but of course there is no ...


Adding a semicolon at the end of your command will suppress its output. result = Solve[...]; The result is saved in the variable result for further processing. You can get the constants by, for example, constant1 = C1 /. result;


f[x_] := x^2 - 1; df = D[f[x], x]; lastX = .7;(*guess*) k = 1;(*counter,just in case*) err = Infinity; SetOptions[$FrontEnd, PrintPrecision -> 16] r = First@Last@Reap@While[err > 0.000001 && k < 10, Sow[{k, err, lastX}]; currentX = lastX - f[lastX]/(df /. x -> lastX); err = Abs[f[currentX] - f[lastX]]; lastX = ...


Starting with your code, corrected as in my comment, z[x_, y_] := x + y*I F[z_] := (25*Pi*z*I)/(1 + 10*Pi*z*I) you can plot the imaginary part of F as follow ContourPlot[Im[F[z[x, y]]], {x, -.2, .2}, {y, -.2, .2}, PlotRange -> All, Contours -> Range[-5, 5, .5], ContourLabels -> True] and similarly for other quantities. Many different ...


The thing that made this work in the end was using dummy variables as the function parameters. This then allowed me to use /. to replace variables. solution[mm_, gg_] := NDSolve[{eqn /. {m -> mm, g -> gg}, z[0] == 0, z'[0] == 0}, z[t], {t, 0, 10}] I think this is a pretty unintrusive solution, since it only affects one line of code and I can ...


In the Standard Evaluation Sequence the heads of expressions are evaluated first: If the expression is a raw object (e.g., Integer, String, etc.), leave it unchanged. Evaluate the head h of the expression. Evaluate each element of the expression in turn ... Therefore since f[1] is the head of f[1][2] it will evaluate if it has a definition that matches. ...


AddAssumption[assumption_]:=$Assumptions=DeleteDuplicates[$Assumptions&&assumption] You need to also check which functions use $Assumptions by default. Simplify, Refine and FullSimplify use it. To reset the assumptions use: $Assumptions=True Example: AddAssumption[x>0] Simplify[Sqrt[x^2]] Out: x

Top 50 recent answers are included