Are stars like our sun continous, or do they have boundaries?

Unlike planets like earth the sun is a star made of gas and radiating light outward indefinitely. I see no reason that the gas and radiating light would travel and decay by density countinously, which might make it difficult to tell where it begins and ends.

For a distance from the center can we tell what is considered inside the sun?

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u/DotBeginning1420 — 2 days ago
▲ 1.7k r/physicsmemes+1 crossposts

Candela is not a fundamental unit

>Candela is a basic SI unit to measure illuminous intensity. It takes into account human eye recptors sensitivity to different color wave lengths, which can't be expressed by a simple linear, square or exponantial relationship, so it is determined experimentally! Also it is defined now by watt/angle (stradian) (watt=Joul/second)! !<

u/DotBeginning1420 — 28 days ago

What is sin(sin(sin(...sin(x))))? Can we find an upper bound?

Here is something interesting I found about sin(x). You can see and prove by derviation that the maxima, minima and inflection points of the nested sin() are preserved for each. The more nested the sine, the more the range of values decrease towards 0.

I wonder if we know how many nested sines we have, we should know how much the function decreases? Can you find it somehow?

u/DotBeginning1420 — 1 month ago

Find a 3x3 magic square of 0's

Find a 3x3 magic square of integers that satisfies these requirements:

  1. All numbers are integers (ℤ) and different from each other.
  2. Each row, column, and diagonal add up to 0.

>!Hint:!< >!check if the number at the center of the square can be 0 or not.!<

>!Example: !<

>!-1 +4 -3!<
>!-2 0 +2!<
>!+3 -4 +1!<

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u/DotBeginning1420 — 1 month ago

Magic square of negative numbers

Can you make a 3x3 magic square, not the original one, but with negative numbers?

  1. All numbers are different from each other.
  2. Each row, column and diagonal add up to 0.
  3. The number in the center of the square can't be 0.
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u/DotBeginning1420 — 1 month ago

The most common causes of death worldwide

>!Diabetes increases the risk for developing kidney diseases (diabetic nephropathy).!<

u/DotBeginning1420 — 2 months ago