New answers tagged

1

Try using Rationalize Binomial[0.19999999999999996//Rationalize,1/5]//N = 1.


2

Curiously this works f[x_, y_] := y + 2*4^(x + y - 1) - 10; g[x_, y_] := 4/(2*y - 3)^(1/2) + 2^(2 - x - y) - 5; Solve[{f[z - y, y] == 0, g[z - y, y] == 0, x + y == z}, {x, y, z}, Reals]


1

Unfortunately the following is not a solution, but an observation that grew too long for a comment. At first, I thought that the problem may be the fact that the initialization and number of steps should be given as arguments to RulePlot rather than to TuringMachine, so I tried: Clear[separate] separate := RulePlot[ TuringMachine[ {{state_, ...


0

I don't know what's wrong with the export,but a little bit change will do the job right. You could change LegendFunction -> "Frame" to LegendFunction -> (Framed[#, RoundingRadius -> 4]&) and run it again.


10

Open menu Format > Edit Stylesheet... and paste this below the "Inheriting base definitions from" cell: Cell[StyleData["Input"], StyleKeyMapping -> {}] Choose Yes when prompted to "interpret the text" then close the Private Style Definitions Notebook. This should remove these automatic Cell conversions from Input cells ...


10

That is a known bug in 12.1.1. WRI is going to publish a new build. Issue and workaround see here: https://community.wolfram.com/groups/-/m/t/2006722 Disabling spell checking helps in the mean time: Preferences 
> Interface > Check spelling as you type


0

Alas, even in the new release 12.1.1 which supposedly has 1000 bug fixes, that one wasn't fixed. So it seems that the interest in fixing this is basically zero. This is very unfortunate as the situation as it is now is so unworkable that it prevents me to upgrade to Mma 12, which in turn is a pre-condition to upgrade to macos Catalina. So all is stalled ...


4

The repository function FromIsoTimeStamp will correctly parse the Zulu and offset parts of ISO dates. For example: isoDateString = "2017-04-28T01:50:52.000Z"; ResourceFunction["FromISOTimestamp"][isoDateString] Correctly returns a GMT date as desired.


2

This seems to be fixed in 12.1.1 (at the latest):


4

This seems to be fixed in 12.1.1, DSolve and DSolveValue give the same result as in the workarounds posted:


1

This seems to be fixed in 12.1.1: $Version (* 12.1.1 for Mac OS X x86 (64-bit) (June 9, 2020) *) ClearAll[y, x]; ode = D[y[x], x] - (y[x]^2 + 1)/(Abs[y[x] + (1 + y[x])^(1/2)]*(1 + x)^(3/2)); TeXForm[ode] (* y'(x)-\frac{y(x)^2+1}{(x+1)^{3/2} \left|y(x)+\sqrt{y(x)+1}\right| } *)


1

This seems to be fixed in 12.1.1:


0

This was originally confirmed by Wolfram Support to be a bug and has now been fixed in 12.1.0: PolarPlot[Tan[t]^4, {t, 0, 2 Pi}] This also fixes the following snippets from the comments: ParametricPlot[Tan[t]^4 AngleVector[t], {t, 0, 2 Pi}] PolarPlot[Tan[t]^(2 + 5 10^(-15)), {t, 0, 2 Pi}]


5

Another approach to a workaround, which is to factor the solution into two operations, solve over the complexes and then solve that solution over the reals: foo = Reduce[{f[x, y] == 0, g[x, y] == 0}, {x, y}] Solve[foo && (x | y) ∈ Reals, {x, y}, {C[1]}] (* {{x -> -(19/2), y -> 19/2}, {x -> 0, y -> 2}} *) Asking Mathematica to solve ...


6

Seems, Solve has problems to determine, whether the square root in the denominator is real. One workaround is Solve[{f[x, y] == 0, (g[x, y] // Together // Numerator) == 0}, {x, y}, Reals] (* {{x -> -(19/2), y -> 19/2}, {x -> 0, y -> 2}} *)


1

I do not agree that this is a bug in Mathematica. Mathematica has built-ins with certain optimizations. It is well done and a competitive CAS. The solution from Bob Hanlon seems to be too difficult for the other engaging themself in answering this question. So be aware that: Reduce[{f[x, y] == 0, g[x, y] == 0}, {x, y}] C[1] \[Element] Integers &&...


10

This is a critical issue and should be treated as a bug in equation solving functionality. Even though Reduce is more powerful for detecting special solutions of systems of transcendetal equations (see e.g. What is the difference between Reduce and Solve?) it fails here either. Nontheless we restrict the following analysis to Reduce to get rid of those ...


9

$Version (* "12.1.0 for Mac OS X x86 (64-bit) (March 18, 2020)" *) Clear["Global`*"] f[x_, y_] := y + 2*4^(x + y - 1) - 10; g[x_, y_] := 4/(2*y - 3)^(1/2) + 2^(2 - x - y) - 5; Solve[{f[x, y] == 0, g[x, y] == 0}, {x, y}, Reals] (* {{x -> -(19/2), y -> 19/2}} *) Perhaps the issue arises because "Solve uses non-equivalent ...


13

Not answer to why, since I do not know why Mathematica does not find it under real. I think this looks like a bug. But to find both solutions, use f[x_, y_] := y + 2*4^(x + y - 1) - 10; g[x_, y_] := 4/(2*y - 3)^(1/2) + 2^(2 - x - y) - 5; Solve[{f[x, y] == 0, g[x, y] == 0}, {x, y}, Rationals] Maple finds both under Real


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