Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options not deleted user 53677

Questions related to the calculus and analysis branches of Mathematica, including, but not limited to, limits, derivatives, integrals, series, and residues.

3 votes

How to quickly calculate the limit of integral with parameters

L'Hôpital's rule needs ~10% of the calculation time Normal[Series[Integrate[t*Log[1 + t*Sin[t]], {t, 0, x}] , {x, 0, 4}]]/Normal[Series[(1 - Cos[x^2]) , {x, 0, 4}]] (* 1/2*)
Ulrich Neumann's user avatar
2 votes
Accepted

How to use L'Hospital's rule for abstract functions

L'Hospital's rule is applicable if the Limit would give a singular expression 0/0 Try Limit[(a*f[h] + b*f[2 h] - (a + b) f[0])/h, h -> 0, Analytic -> True] (*(a + 2 b) Derivative[1][f][0]*)
Ulrich Neumann's user avatar
1 vote

Solving Integral in analytic form takes too long

Use some Assumptions to get a fast evaluation. For simplified integrand (x^2+y^2->x^2, y-h->y) Mathematica evaluates FullSimplify[Integrate[1/Sqrt[x^2 + (y - t)^2 ], {t, -c, c}, Assumptions -> {c > 0 …
Ulrich Neumann's user avatar
2 votes
Accepted

How to verify the integral remainder of this integral formula?

Answer to your first question: Series[Integrate[f[x], {x, 0,h}] - (h/2 (f[0] + f[h]) + \[Alpha] h^2 (f'[0] - f'[h])), {h, 0,3}] (* f''[0](\[Alpha]-1/12)h^3+O[h^4]*) Optimal \[Alpha]==1/12 The answer …
Ulrich Neumann's user avatar
1 vote

How to calculate the derivative of the solution of DSolve?

For a simple solution try DSolveValue diffPD = {2/r*cA'[r] + cA''[r] == \[Phi]^2/R^2*cA[r], cA[R] == cAR, cA'[0] == 0} solPD = DSolveValue[diffPD, cA, r] the solution of the ode is solPD[r] and the d …
Ulrich Neumann's user avatar
2 votes

Why doesn't Mathematica integrate this?

Mathematica has problem to handle the Abs inside the argument of DiracDelta (Thanks to the answer of @MichaelE2) Knowing DiracDelta[v-Abs[x]]=DiracDelta[v-x]+DiracDelta[v+x] Mathematica evaluates the …
Ulrich Neumann's user avatar
0 votes

Why doesn't Mathematica integrate this?

final answer DiracDelta[v-Abs[x]]==DiracDelta[Abs[x]-v] only contributes to the integral if the argument v-Abs[x] becomes zero. That's only possible if v>=0! The integral evaluates to Integrate[A*Exp[ …
Ulrich Neumann's user avatar
2 votes

How to interpret these integrations with DiracDelta?

The integral exists and the first result is ok. Obviously Mathematica can't transform the nonlinear argument y-x^2 in your second approach Integrate[DiracDelta[y - x^2], {y, 0, 2}, {x, -1, 1 - y}]. Th …
Ulrich Neumann's user avatar
4 votes

Solve command does not solve this equation!

supplement to @Bob Hanlon 's answer ContourPlot shows the possible solution directly: ContourPlot[f[n, x] == 0, {n, 0, 15}, {x, -5, 5}, MaxRecursion -> 4, FrameLabel -> Automatic] addendum The …
Ulrich Neumann's user avatar
1 vote

Complicated integration

What about NIntegrate (with parameter f2g=f[z]^2 g[z]) : int[f2g_?NumericQ] :=NIntegrate[(x*Exp[-2*x]*(y^(-0.5)*Exp[-2*y]))*Exp[-(E1*Exp[-x]*Exp[-y]/(f2g))], {x, 0, Infinity}, {y, 0,Infinity}] Plot[ …
Ulrich Neumann's user avatar
2 votes

Challenging integral for Gaussian average

If a numerical solution is ok try int[a_?NumericQ, b_?NumericQ] := NIntegrate[Exp[-x^2/2]/Sqrt[2 Pi] Sqrt[1 + a^2 Sinh[b x]^2], {x, -Infinity,Infinity}] Plot3D[int[a, b], {a, 0, 1}, {b, 0, 2}, AxesL …
Ulrich Neumann's user avatar
6 votes

Derivative for arbitrary number of times

Try f[t_] := Exp[k t] Sinh[t/n]/(Cosh[t/n] - a) and for example the third derivative f'''[0] evaluates like this Derivative[3][f][0] (*-(3/((1 - a)^2 n^3)) + 1/((1 - a) n^3) + (3 k^2)/((1 - a) …
Ulrich Neumann's user avatar
0 votes

Integrate ArcTanh or ArcTan

Try f = Integrate[ 1/(Sqrt[(a + b^2/(4 c^2)) x^2 - (1 -2/(3 c))] + (b/(2 c) x)) , {x,1, a}, Assumptions -> { a > 1, b > 0, c > 1}] and Mathematica evaluates an unique solution (*(1/(4 a c))(-2 b …
Ulrich Neumann's user avatar
6 votes
Accepted

Mathematica doesn't give an answer to what wolframalpha answers

Mathematica Sum just returns input means MMA doesn't find an analytical answer The sum seems to be convergent SumConvergence[(1/n)^(n), n] (* True *) Numerically result NSum[(1/n)^(n), {n, 1, Infin …
Ulrich Neumann's user avatar
2 votes

Newton Method with a Parameter in the equation

Perhaps it's easiier to use NestList? f[x_] := Exp[-x] - a x NestList[# - f[#]/f'[#] &, 0, 3] // Simplify %/.a->1. (*{0, 0.5, 0.566311, 0.567143}*)
Ulrich Neumann's user avatar

1
2 3 4 5
21
15 30 50 per page