4 ms·

Then take 10 and divide it by -10 = -1. 10 / -5 = -2. 10 / -0.5 = -20. So from the other side of the y-axis it behaves the exact opposite. It goes to minus infi

by v4vvdq 2y ago

Then take 10 and divide it by -10 = -1. 10 / -5 = -2. 10 / -0.5 = -20. So from the other side of the y-axis it behaves the exact opposite. It goes to minus infinity. So at x=0 we would have infinity and minus infinity at the same time. Imho that is why it is undefined.

WithinReason 2y ago
on computers you can have negative zeros
- recursive 2y ago
  Negative zero is equal to zero, so it's not really a distinct number, just another representation of the same value.
  - epidemian 2y ago
    It's equal (as in, comparing them with == is true), but they are not the same value. At least in IEEE 754 floats, which is what most languages with floating point numbers use. E.g., in JS: > 1 / 0 Infinity > 1 / -0 -Infinity > 0 === -0 true > Object.is(0, -0) false
    - eru 2y ago
      Yes. In a language like C or Rust, you can cast your +0.0 and -0.0 to an integer, and print out the bit pattern. They are different.
    - recursive 2y ago
      I think you're misunderstanding me. They are the same value, but a different representation. The equivalence of the value can be shown with math, and has nothing to do with the implementation details of IEEE 754.
  - atsmyles 2y ago
    -0 is a notation for 1 / -infinity, so it is distinct. For addition it is not.
- pasquinelli 2y ago
  that's really just an encoding of the number to help you understand how the hell you got here
eqvinox 2y ago
In IEEE 754 math, x/0 for x < 0 is in fact negative infinity. >>> np.float64(-1.)/0. -inf >>> np.float64(1.)/0. inf And you're exactly right, 0/0 is NaN in 754 math exactly because it approaches negative infinity, zero (from 0/x), and positive infinity at the same time.
numpad0 2y ago
I always thought the answer to verbal query "let y=1/x, x=0, find y" was "Well, the answer is the Y axis of the plot". Surprising that people have to be reminded that X can be signed. I've had similar conversation IRL.
- ConspiracyFact 2y ago
  You seem to have your axes confused. The value of y can’t be “the y-axis”, which is the line x = 0 (for all values of y).

by v4vvdq 2y ago

WithinReason 2y ago

on computers you can have negative zeros

recursive 2y ago
Negative zero is equal to zero, so it's not really a distinct number, just another representation of the same value.
- epidemian 2y ago
  It's equal (as in, comparing them with == is true), but they are not the same value. At least in IEEE 754 floats, which is what most languages with floating point numbers use. E.g., in JS: > 1 / 0 Infinity > 1 / -0 -Infinity > 0 === -0 true > Object.is(0, -0) false
  - eru 2y ago
    Yes. In a language like C or Rust, you can cast your +0.0 and -0.0 to an integer, and print out the bit pattern. They are different.
  - recursive 2y ago
    I think you're misunderstanding me. They are the same value, but a different representation. The equivalence of the value can be shown with math, and has nothing to do with the implementation details of IEEE 754.
- atsmyles 2y ago
  -0 is a notation for 1 / -infinity, so it is distinct. For addition it is not.
pasquinelli 2y ago
that's really just an encoding of the number to help you understand how the hell you got here

eqvinox 2y ago

In IEEE 754 math, x/0 for x < 0 is in fact negative infinity. >>> np.float64(-1.)/0. -inf >>> np.float64(1.)/0. inf And you're exactly right, 0/0 is NaN in 754 math exactly because it approaches negative infinity, zero (from 0/x), and positive infinity at the same time.

numpad0 2y ago

I always thought the answer to verbal query "let y=1/x, x=0, find y" was "Well, the answer is the Y axis of the plot". Surprising that people have to be reminded that X can be signed. I've had similar conversation IRL.

ConspiracyFact 2y ago
You seem to have your axes confused. The value of y can’t be “the y-axis”, which is the line x = 0 (for all values of y).