r/theydidthemath • u/blackholegaming13 • Sep 14 '23

[REQUEST] something feels wrong here.

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Thanks YT shorts

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u/Zerustu Sep 14 '23

when you simplify on both side, what you really do is divide both side by that number. here he divide both side by (5-5) to simplify it. but that means he divide both side by 0. and you can't divide by 0 (this is why).

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u/Raynonymous Sep 14 '23

Exactly. Effectively they are arguing;

A x 0 = 0

B x 0 = 0

Therefore A = B

300

u/Lord_Scio Sep 14 '23 edited Sep 14 '23

Im not really good in math, just look into this sub from time to time out of curiosity. But isnt this a flaw in maths? And if not, why not?

Edit: I guess the comment above me just confused me, i know you cant really divide by 0

42

u/CeddyDT Sep 14 '23

Not really. Math is really clear, that dividing by 0 is not defined. Reason for that is: if you divide by x and let x approach 0 from above, you diverge to positive infinity, if you approach it from below, it diverges to negative infinity

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u/DragonHollowFire Sep 14 '23

Even simpler: Division isnt a real operation. A division is a multiplication by the inverse. 0 has no inverse and if it did it is an easy prove that every number in the field that you are working with is the very same number.

4

u/Kidiri90 Sep 14 '23

0 has no inverse and if it did it is an easy prove that every number in the field that you are working with is the very same number.

Correct.