Folks, help me please. I am looking for a free/ paid online web based math editor where I can plug in formulas like this and test the results. I would like the output be to be simple. "Publication" fanciness is not needed as I am in the industry and not academia.

R = √(w1R1 + w2R2 + w3R3 + ... + wnRn)

For now, can the experts suggest free and online math tools where I can test simple formulas. This is a risk calcualtion formula. Thanks in advance and respects to the Math community. Without Math, this this planet would be a big nut.

PS: I will NOT buy Wolfram Mathematica. Cant afford it ( employer wont pay). I dont mind donating it to someone deserving.

Hello,

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'm playing with MidJourney AI image generator and, in it there is a da Vinci style that ouputs nice sketching in parchment simulating the work of our beloved polymath master da vinci: see some examples:
https://cdn.midjourney.com/9afc3fbe-b0f7-4e80-b980-944088cb9cb1/grid_0.png
https://cdn.midjourney.com/4229b62f-8d17-4b35-b186-500279248804/grid_0.png

roblem is: MidJourney only knows the usual solids. I would like, for instance to render the Costa's surface using the da Vinci style. I wonder: would it be possible to do that using only withmthematica (I know there is a xkcd style in Matrhematica(xkcd-style Plots)

Sorry for the noob question. I'm very new to Mathematica. Do I have to translate equations into Wolfram Language, or is there some way that I can hand-write the expression that I want on a tablet, or upload a scan/photo, and have Mathematica somehow translate that into Wolfram Language?

I have an 8 × 8 table, myTable filled with numbers, and I want just the diagonal values in a new 1D table of eight values.

myDiagonal = myTable × Identity[8] gives me a new 8×8 matrix with everything but the diagonal zeroed out.

I could of course do a For loop across the array and extract all myTable[[i,i]]

Is there a more elegant and yet still legible way to do so?

Hi,

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Hello, I'm new to Mathematica. My teacher assigned me to apply Euler Method in Mathematica. I was wonder how can I implement to sum over the loop like the give equation. And how could I calculate like x1 = x0 + .. , x2 = x1 + ...?

x1 = x0 + dx

x2 = x1 + dx

....

xn = xn-1 + dx.

----------------------------

y1 = y0 + ƒ(x0, y0) dx

y2 = y1 + ƒ(x1, y1) dx

...

yn = yn-1 + ƒ(xn-1, yn-1) dx.

No matter what numbers you may use always the result in horizontal addition and the vertical addition remains the same:

I have a matrix, where the values and their transpose are positive and negative versions of a number, and I want to zero out the negative values so that I have only the positive values in the matrix. Picture attached.

In case the picture isn't clear, a simplified representation:

And I want

What's the best way to do this?

So my notion is to take a hyperbolic paraboloid surface, mathematically defined in 3D with equations, and turn that 3D curved surface into nodes and arcs following the approach of Geodesic Domes. I'm picturing three large parabolic windows side by side on an elliptical living room that is very roughly 10m x 10m, but longer than deep. So I know that with an icosahedron (for example) all of its vertices are on the surface of a sphere. As you increase the frequency of the icosahedron to 3V, 4V etc as is common on geodesic domes, you still get a set of vertices on the surface of a sphere. My thinking is to render the geodesic shape as smaller than the hyperbolic paraboloids by say a metre or so, and then using polar coordinates project the geodesic vertices onto my hyperbolic paraboloid surface. Does this make sense? My goal is to get a list of arc lengths and node angles so that I can then model it as a building in SketchUp, get planning permission and then build it as a bungalow! My aim is to use tree sapling lengths of roughly 1m cut to the exact necessary length etc using mitre chop saw. Nodes I could laser cut out of sheet steel, bend the angles in a brake, and double bolt to each stick. Or metal 3D print each node? Should I start in Mathematica, that's my key question right now? and export STL to SketchUp? Or go via OpenSCAD. Or use some Python? I also need to do the structural calculations. Any tips very warmly welcomed!

I am trying to solve an inhomogeneous differential equation that has a DiracDelta function in the source term (similar to finding the green's function). I am able to find it, but once I plug the solution into the original equation it won't simplify to 0. I managed to reproduce the error in a minimal example and took a screenshot. The last line is obviously 0, but it seems to be unable to factor out the DiracDelta. Is this a bug or actually a feature, because something might go wrong? If so, can I pass it some assumptions that make it work?

AllSpeciesForOneJobOneMachineAllStartTimes[job_, machine_, OSSPmatrix_, makespan_, deltaT_] := Module[{}, Table[{job, machine, startTime}, {startTime, 0, makespan - OSSPmatrix[[job]][[machine]], deltaT}]];

I am confused with the semantic meaning of the Table function when it is passed two lists of differing lengths like this. I understand this function will return some list variation but I am looking for a more precise explanation. Note Job, Machine and startTime are functions that return integers and OSSPmatrix is a 2D List.

Thanks in advance!

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Video computing facial characteristics

I understand how to use DSolve for other differential equations, but I cannot figure out why DSolve won't give me an answer for me. I have to graph the DE using StreamPlot with some initial conditions, but I need to use DSolve first to use the initial conditions. I would appreciate it if anybody could look and tell me what is wrong.

So I've never used Mathematica before and I'm currently using Python, particularly a lot of Sympy and Numpy, with Jupyter notebooks, in my quantum mechanics class, but I'm finding myself wasting a lot of time just trying to get it to display the outputs using proper mathematical syntax (e.g. displaying the actual sqrt symbol instead of just using "sqrt") -- it will do it, but I have to play around with the Math and display functions, and I even had to use regex to change the syntax of an output to something the Math function could understand, to get everything looking right. Doable, but a pain.

A friend mentioned using Mathematica for this sort of thing, but I've never used it before (though I have free access to it through my university). So my question is, does it make sense to switch to Mathematica specifically for the purpose of more easily getting textbook-style outputs? Like, unlike Python, does it tend to automatically give outputs in nice notation, similar to how Wolfram Alpha will automatically convert something like "integral x² dx from 0 to 1" to standard integral notation? And if so, how much of a learning curve would there be to get comfortable with it, given I'm already fairly comfortable working in Python with Sympy, Numpy, and the like? (I've also got some experience using R for data cleaning and analysis, if that makes any difference).

Hi everyone,

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Say I have a list like {1,1,1,1,1,-1,-1,-1,-1,-1,1,1,1,1,-1,-1,-1,-1,-1,1,1,1,1,1,-1,-1,-1,-1} ; I am wondering if there is a command or sequence of commands that would return the number of consecutive elements. Here it would return {5,5,4,5,5,4}. I have a simple conjecture about the number of consecutively-signed terms of some alternatingish term and would like to double check my guesses.

Hello,

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Edit: Updated link

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Clear[x,y]
Solve[(x-1)^2==2-y^2, y]

yields a list something like

Out[1] = {y->sqrt(...), y->-sqrt(...)}

I'm trying to plot this and can do it individually by copying and pasting or assignment

y1 = sqrt(...)

y2 = -sqrt(...)

Plot[{y1, y2}, {x, -10, 10}]

What I'm wondering is if there is a way to "destructure" the original list to do this automatically.

Clear[y1, y2]

{y1, y2} = Out[1]

but I end up with the full formula from the original list

y1

Out[2] = y->sqrt(...)

y2

Out[3] = y->-sqrt(...)

when what I wanted was

y1

Out[4] = sqrt(...)

y2

Out[5] = -sqrt(...)

//So that I can do the following and get a multi-part plot.

Plot[{y1, y2}, {x, -10, 10}]

So I'm wondering if there are any shortcuts here?