675
"Do your own research" they say. (lemmy.world)
submitted 2 years ago by to c/skeptic@lemmy.world
100 comments fedilink hide all child comments
 
you are viewing a single comment's thread
view the rest of the comments
[–] 51 points 2 years ago (3 children)

Those same people do math incorrectly and shout at everyone else to do it their way.

  • permalink
  • fedilink
  • source
  • hideshow 6 child comments
    •
  • [–] 35 points 2 years ago (4 children)

    2+2=5

    Don't take my word for it research about it yourself there are lots of good videos on YouTube the government and science liars don't want you to know the truth /s

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 8 child comments
    •
  • [–] 18 points 2 years ago (1 child)

    2+2=5

    For extrem values of 2.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 2 child comments
    •
  • [–] 16 points 2 years ago (2 children)

    For those confused

    2.25+2.25=4.5 rounds to 2+2=5

    2.5+2.5=5 truncates to 2+2=5

    Both can crop up in programming, depending on the situation.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 4 child comments
    •
  • [–] 3 points 2 years ago (1 child)

    2.25 + 2.25 = 4.5

    If you add two floats together then the output is a float, if you add an int and a float together the output is a float. Computers will always perform the calculation as is, unless you explicitly tell them to perform a rounding operation.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 2 child comments
    •
  • [–] 6 points 2 years ago

    However, if you stuff them into an int at the last minute, you can get that effect.

    Under the hood, it's floats. On the output, it's ints.

    It's obvious and silly with small examples. The problem can creep in when you are using larger libraries or frameworks.

  • permalink
  • fedilink
  • source
  • parent
  • [–] 5 points 2 years ago* (last edited 2 years ago) (1 child)

    Just look at those viral math problems. I recently saw one that was something like (1+2*3)*(1*0) and most comments were arguing if it was 7 or 9

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 2 child comments
    •
  • [–] 10 points 2 years ago (1 child)

    I think you mean (1+2*3)*(1*0).

    Escape your asterisks, kids.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 2 child comments
    •
  • [–] 8 points 2 years ago (2 children)

    I mean, it doesn't matter.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 4 child comments
    •
  • [–] -1 points 2 years ago (1 child)

    It does if you forgot everything you learned in school

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 2 child comments
    •
  • [–] 3 points 2 years ago (3 children)

    Of course, there's also the times where we just make the research hard to do.

    Like, we teach kids PEMDAS, but then don't actually follow PEMDAS in the original textbooks that introduce it and definitely not in common math or physics texts.

    Like, you'll see 1/2√r in Feynman's lectures being written not to represent ½*√r = √r / 2 as pemdas would suggest, but 1/(2*√r).

    Similarly, the original textbooks that introduced PEMDAS, if you read them, actually followed what you might call PEJMDAS, where multiplication via juxtaposition is treated as binding tighter than explicit multiplication, so 1÷2(2+3) would be interpreted not as ½(5) but as 1 ÷ (2 * 5), but they considered that so obvious they didn't bother to explicitly spell it out in the rules.

    And now we have Facebook memes and tiktok livestreams arguing about what 1÷2(2+3) actually means.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 6 child comments
    •
  • [–] 3 points 2 years ago (1 child)

    Also by the time you've learned order of operations, you've outgrown the ÷ operator. You would never write 1 ÷ (2 * 5), you would write it with a proper numerator and denominator like anyone outside of elementary school would.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 2 child comments
    •
  • [–] 3 points 2 years ago

    I hate these math problems you see on social media. No one would write that way or code that way. It is ambiguous, and even if it weren't it is still hard to figure out. I think in my entire career I have seen one single line of code that took PEMDAS to sort out, I remember that line and the programmer told me that they were exploiting a feature of the complier to get slightly faster results. He was an annoying person

  • permalink
  • fedilink
  • source
  • parent