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| bio | website | |
|---|---|---|
| location | China | |
| age | ||
| visits | member for | 10 months |
| seen | 16 hours ago | |
| stats | profile views | 146 |
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Nov 22 |
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Insert $+$, $-$, $\times$, $/$, $($, $)$ into $123456789$ to make it equal to $100$ My computer failed to finish running this code, but you've told me the keypoint!! With your hint I've got a way to solve, wait for a moment, I'll post an answer to my own question for the first time :D. BTW, you get how many solutions? I want to check whether my solution is complete or not. |
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Nov 22 |
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Insert $+$, $-$, $\times$, $/$, $($, $)$ into $123456789$ to make it equal to $100$ Well, I think my solution for $+$, $−$, $×$, $/$ is almost same as Chris', but this method is really hard to extend to the case with $($ and $)$ added in… |
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Nov 22 |
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Insert $+$, $-$, $\times$, $/$, $($, $)$ into $123456789$ to make it equal to $100$ Er… this post seems not to contain the solution with ( and ). |
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Nov 22 |
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Insert $+$, $-$, $\times$, $/$, $($, $)$ into $123456789$ to make it equal to $100$ @kguler Oh! That's a mistake of the code, let me correct it. |
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Nov 21 |
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ArcTan[0,0] numeric approximation Then why doesn't ArcTan[0.,0.] return Interval[{-π/2,π/2}]? |
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Nov 21 |
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ArcTan[0,0] numeric approximation But the behaviour of ArcTan[0.0, 0.0] is still unresolved, also, why doesn't ArcTan[0, -0.] return -Pi/2? |
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Nov 21 |
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ArcTan[0,0] numeric approximation @J.M. I think your example is because of the…er…strange property of $MachinePrecision, according to the document, `$MachinePrecision` is numerically Equal to MachinePrecision, but `$MachinePrecision` uses arbitrary precision computations with machine precision resolution. In fact NumberForm@N[0, $MachinePrecision] is 0, while NumberForm@N[0, MachinePrecision] is 0.… |
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Nov 17 |
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How to import all files of a folder at once? @rm-rf I supplied the version information of my Mathematica and a snapshot: those commas and backslashes and quotes are not added by me. |
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Nov 15 |
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Prevent Part[] from trying to extract parts of symbolic expressions BTW, notice that deleting the _Real in functions will lead to an opposite result. |
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Nov 15 |
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Prevent Part[] from trying to extract parts of symbolic expressions Have you considered changing the order? For example: (list /. list -> {1, 2, 3})[[2]] |
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Nov 14 |
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How to scale vectors in VectorPlot? Er…we can also use Norm instead of EuclideanDistance, right? |
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Nov 13 |
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How to scale vectors in VectorPlot? This is a little different from OP's intention: he wants the length of arrows to somewhat represent the size of the vector. |
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Nov 13 |
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How to scale vectors in VectorPlot? Oh, you finally come! Why not log in？ |
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Nov 13 |
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GIF won't speed up anymore when “DisplayDurations” is smaller than 0.015? @Szabolcs _I guess this is the timer IE uses for GIF display. _, er… do you miswrite Chrome as IE? Seems that the resolution of IE is only 0.1 at least in my computer. |
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Nov 12 |
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GIF won't speed up anymore when “DisplayDurations” is smaller than 0.015? @F'x Now I only keep 2 frames for this GIF but I still feel it a little slow and the current GIF is so crude… if only IE could give a better support for GIF! |
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Nov 12 |
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GIF won't speed up anymore when “DisplayDurations” is smaller than 0.015? @Ajasja OK, I should have search the Internet more carefully… and I didn't expect that so quick can I get a chance to use the expression I made above!! |
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Nov 10 |
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FindRoot errors Oh, I forgot to mention that a higher WorkingPrecision (for example 20) in FindRoot is still needed, and the option MaxIterations isn't necessary. |
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Nov 10 |
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FindRoot errors If you had read the link and all the comments below carefully, you should have noticed that what you need isn't Rationalize[…, 10^-16] but Rationalize[…, 0] for your 2nd sample; SetPrecision[…, Infinity] will also work. BTW I really suggest you to clean up your sample a little (your 2nd sample is not even available for direct running! ) so it can attract more attention. |
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Nov 9 |
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FindRoot errors And I found that the documentation has already given a explanation for SetPrecision[…, 0] and Rationalize[…, Infinity], not difficult to understand. A somewhat related question is this. At last, let me give the same sigh as @b.gatessucks : this function is so sensitive! |
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Nov 9 |
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DeleteCases messing with my mind Er…can this be concluded as: we should avoid using a real number for the step size of loops and recursions? |
