Math Memes

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Memes related to mathematics.

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Simplify (sh.itjust.works)

submitted 8 months ago by sjmarf@sh.itjust.works to c/mathmemes@lemmy.blahaj.zone

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[–] MonkderVierte@lemmy.ml 2 points 8 months ago (3 children)

(a)(b) basically means a*b

Ok, wtf. Why write it like this then?

[–] superkret@feddit.org 27 points 8 months ago (1 children)

To make sure what's inside the brackets is resolved internally before they're multiplied with each other.

 (a)  (b)   =   a * b  
(a+1)(b+1) =/= a+1*b+1

[–] brbposting@sh.itjust.works 2 points 8 months ago* (last edited 8 months ago)

TIL this notation makes it math the text up

(a)  (b)   =   a * b  
    (a+1)(b+1) =/= a+1*b+1

Edit: hmm, already shows in a code block so adding backticks didn’t do anything

[–] greybeard@lemmy.one 6 points 8 months ago (1 children)

To expand on what superkret said, in math there is the concept of "order of operations". That is to say, every function in math (add, multiply, divide) has to be done in a specific order. Since multiplication comes before addition and subtraction, if you have a formula like a-xb-x, you will do xb first, then a minus the result of x*b, which would give a very different result than if you did a-x and multiplied that by b-x. This is where the parenthesis come in. You are basically saying, resolve every section in parenthesis first using the proper order, then resolve the rest.

My original example (a)(b) was over simplified, because there is no conflict there. You can also do things like (ax)-(bx). If there is no operator though, it is assumed multiplication, and I'm unsure why that is.

[–] starman2112@sh.itjust.works 3 points 8 months ago* (last edited 8 months ago) (1 children)

Putting multiple asterisks in a comment makes it look italicized, at least on some Lemmy clients. If you want to have asterisks with *unitalicized* text, you gotta put a \ behind the * to negate the change

[–] greybeard@lemmy.one 2 points 8 months ago

Oops, I should have previewed it, thanks for pointing it out.

[–] Jyek@sh.itjust.works 2 points 8 months ago (1 children)

Because you wrote a lot less when writing it this way. Groups of terms beside each other are multiplying each other and you have to solve what's inside of those groups before multiplying them together.

[–] SmartmanApps@programming.dev 1 points 7 months ago

Groups of terms beside each other are multiplying each other

Actually the whole thing is a single Term. Terms are separated by operators and joined by grouping symbols, and there's no operators between the successive brackets.

you have to solve what’s inside of those groups before multiplying them together

You don't have to, but it sure makes the working-out a lot easier if you do!

If a=1, b=2, c=3, d=4, then...

(a+b)(c+d)=(ac+ad+bc+bd)

(1+2)(3+4)=(1x3+1x4+2x3+2x4)=(3+4+6+8)=21

whereas...

(1+2)(3+4)=(3)(7)=(3x7)=21 :-)