Wolfram Mathematica

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4:45 AM

Plot[Probability[Max[x1, x2] < x, {
   x1 \[Distributed] NormalDistribution[0, 1],
   x2 \[Distributed] NormalDistribution[.1, 2]
   }], {x, -10, 10}]

Does anyone know why this yields an empty graph? I'm trying to plot the PDF and the CDF of the maximum of two normally-distributed random variables.

user76284

4:58 AM

Probability[a + b < .1, {
  a \[Distributed] NormalDistribution[0, 1],
  b \[Distributed] NormalDistribution[.1, 2]
  }]

Even this is not working properly.

Probability[
 c < .1, {c \[Distributed] NormalDistribution[1, 2],
  a \[Distributed] NormalDistribution[0, 1]}]

What in the world is going on here.

2 hours later…

Mr.Wizard

7:03 AM

I see this has been closed as "simple mistake ... or else it is easily found in the documentation." The question asks "But I don't get the result I want when I run the following code. What can I do to get it?" So this is not merely complaining that Mathematica doesn't work as OP thinks it should, but an actual request for assistance. Agree/disagree?

Q: How can I plot a parametric equation with ±?

I want to draw a parametric equation with ± like the figure below: But I don't get the result I want when I run the following code. What can I do to get it? ParametricPlot[{x, ±x^2}, {x, 0, 1}, Mesh -> 30, PlotPoints -> 50, AxesOrigin -> {0, 0}]

4 hours later…

xzczd

10:52 AM

@Mr.Wizard Well, though the user is someone I can't help frowning on, I admit this question itself is OK in my view.

8 hours later…

Michael Hale

7:07 PM

@user76284 You have an invisible "discretionary hyphen" (character code 173) inserted after the x2 and before the distributed sign.

Put your cursor after the x2 and press backspace and then evaluate the cell again.

Soft hyphen

In computing and typesetting, a soft hyphen (ISO 8859: 0xAD, Unicode U+00AD SOFT HYPHEN, HTML:  ) or syllable hyphen (EBCDIC: 0xCA), abbreviated SHY, is a code point reserved in some coded character sets for the purpose of breaking words across lines by inserting visible hyphens. Two alternative ways of using the soft hyphen character for this purpose have emerged, depending on whether the encoded text will be broken into lines by its recipient, or has already been preformatted by its originator. == Text to be formatted by the recipient == The use of SHY characters in text that will...

Szabolcs

7:35 PM

@MichaelHale We call it a "pipeline" but in reality it is almost never linear. It is more like a directed acyclic graph. For example, from a we compute b and c, then from c we compute d then from b and d we compute e, then from a and d we compute f then form f and e we compute the final result. A simple chain of functions won't work in practice.

Of course, in principle, I could bundle those intermediate results up into an association ... but it's likely that it'd be hard to stay organized that way. Plus, auto-complete doesn't work on association keys, annoying.