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1h
awarded  Popular Question
5h
comment NDSolve giving the wrong solution?
... the one you showed y=-4*x/(1+3*x). The point is, these are singular solutions. There is a singularity in your ode, which is why NDSolve gives a 1/0 error. So, there is nothing wrong with NDSolve. Notice that DSolve did not solve this.
5h
comment NDSolve giving the wrong solution?
do not have time now, but quick comment: you have non-linear ode. A non-linear ode can admit a singular solution (which can't be obtained from the general solution by giving the constants of integration specific values). Another solution is y=-2. Another is y=(-4*((x^4-2*x^2+1)/(x^4+8*x^3+18*x^2+8*x+1))^(1/2)*x^4-20*((x^4-2*x^2+1)/(x^4‌​+8*x^3+18*x^2+8*x+1))^(1/2)*x^3-4*x^4-24*((x^4-2*x^2+1)/(x^4+8*x^3+18*x^2+8*x+1))‌​^(1/2)*x^2-16*x^3-20*((x^4-2*x^2+1)/(x^4+8*x^3+18*x^2+8*x+1))^(1/2)*x-32*x^2-4*((‌​x^4-2*x^2+1)/(x^4+8*x^3+18*x^2+8*x+1))^(1/2)-16*x-4)/(3*x^4+8*x^3+14*x^2+8*x+3) as well as the..
15h
revised Creating a foggy image
typo
15h
answered Creating a foggy image
1d
comment Steps in row reduction?
Only way I know to look into LU more is by using the {lu,p,c}=LUDecomposition[m] call, where c gives the rows used for pivoting as mentioned in the help. You can't tell how to control the pivoting. There is no option there. from reference.wolfram.com/language/tutorial/… it says LUDecomposition, Inverse, RowReduce, and Det use Gaussian elimination with partial pivoting. That is about it.
1d
comment Output from LinearModelFit not showing entire result
There should be a windows saying show more, show all, etc...? reference.wolfram.com/language/tutorial/…
1d
comment Is this integral solvable?
You can try the free Wolfram cloud, it has Mathematica there for free wolfram.com/programming-cloud/pricing click on the free option. Also can try Wolfram alpha, it is supposed to be able to do integration as well.
1d
answered Different results of a definite integral $\int_0^{\cosh ^{-1}(a)} \frac{1}{\sqrt{a^2 \text{sech}^2(x)-1}}\, dx$
1d
comment How to remove error at large time in NDSolve
it works ok for me using V 10.01 on windows. moved the slider all the way to the right and I see no errors. !Mathematica graphics may be you can upgrade to 10.01
Sep
19
awarded  Generalist
Sep
18
comment Tracking Initialization
@MichaelE2 I know for Manipulate that the following happens, and I would assume the same for DyanmicModule, since Manipulate is just a DynamicModule: The body of Manipulate (the expression part) is checked for valid input/form, but it is not evaluated until Initialization is finished. The question of when Initialization is run or not is separate. But when it needs to be evaluated, then yes, the body/dynamics/expression will wait until Initialization is finished running.
Sep
18
comment Tracking Initialization
I do not think what I said is different from what you are saying. Initialization is evaluated to generate the dynamic expression first time it is needed to be displayed on the screen.
Sep
17
comment Tracking Initialization
I am not sure I understand what you mean by this tracking to be reflected in Dynamic updating Since Initialization is processed once from top down. (to generate the initial expression). Once this is done, Initialization basically goes away.
Sep
17
comment Tracking Initialization
You can always use Print :) DynamicModule[{x}, Dynamic[x], Initialization :> (x = 1; Print["x=2"]; x = 2; Print["x=3"]; x = 3) ]
Sep
17
asked StateSpaceRealization “ControllableCompanion” does not generate ControllableCompanion form from DE
Sep
16
comment Manipulate a parameter within the PlotLabel
f = {1, 2, 3, 4, 5, 6}; Manipulate[ Plot[Sin[f[[g]] x], {x, -2, 2}, PlotLabel -> Row[{"f = ", f[[g]]}]], {{g, 1, "index"}, 1, Length[f], 1, Appearance -> "Labeled"} ]
Sep
14
revised Wrong answer from DSolve?
added error message
Sep
14
answered Wrong answer from DSolve?
Sep
6
awarded  differential-equations