Bad Math Jokes

[WWGD]

New Math Logic book:
" Ultraproducts, America's New Supermodel".

 

[KingGambit]

Ping @DaveC426913

 

[KingGambit]

If 2005 humour is still funny... the English cat 'one two three' and the French cat 'un deux trois' had a swimming race to decide after which country the Channel should be named. The un deux trois cat sank.

Ahh, un deux trois quartre cinq

 

[KingGambit]

All numbers are equal! Let $a$ and $b$ be any two numbers and define$$
c = a + b.
$$Multiply both sides by $a-b$:$$
(a - b)c = (a - b)(a+b).
$$Expand:$$
ac - bc = a^2 - b^2.
$$Rearrange:$$
b^2 - bc = a^2 - ac.
$$Add $ab$ to both sides:$$
ab + b^2 - bc = a^2 + ab - ac.
$$Factorise:$$
(a+b-c)b = (a+b-c)a.
$$Cancel:$$
b=a
$$QED.

Nope, because C = A + B, so
A+B-C = 0,
Let's see.

c = a + b.
$$Multiply both sides by $a-b$:$$
(a - b)c = (a - b)(a+b).
$$Expand:$$
ac - bc = a^2 - b^2.
$$Rearrange:$$
b^2 - bc = a^2 - ac.
$$Add $ab$ to both sides:$$
ab + b^2 - bc = a^2 + ab - ac.
$$Factorise:$$
(a+b-c)b = (a+b-c)a. = 0xB = 0xA
$$Cancel:$$
b=a
$$QED.

 

[WWGD]

Re Pde's, the song " Looking for love in all the wrong places, looking for love in Sobolev spaces.

 

[BillTre]

 

[BillTre]

 

[256bits]

An old car chuggs up a hill of 1 mile for an average speed of 15 mph.
The car then travels downhill for 1 mile.
What must the downhill speed be, so that for the whole trip the average speed is 30 mph.

Ludicrous Speed

 

[collinsmark]

An old car chuggs up a hill of 1 mile for an average speed of 15 mph.
The car then travels downhill for 1 mile.
What must the downhill speed be, so that for the whole trip the average speed is 30 mph.

Ludicrous Speed

As the story goes, Albert Einstein got a delightful chuckle out of this riddle.

(https://mindyourdecisions.com/blog/2019/03/06/this-simple-brain-teaser-delighted-albert-einstein/)

 

[dextercioby]

 

[berkeman]

 

[DaveC426913]

Two mathematicians are eating lunch on a bench in a park. Across from them is a men's washroom.

Over several minutes as they eat, two men enter the washoom and three men leave.

One mathematician nudges his buddy and says: "Now, if one more man enters, there will be zero men in there again."

 

[jack action]

 

[pines-demon]

View attachment 360035​

Based on a recent post of mine: "What kind of integration is Berezin integration?"

$$\int \sin(\mathrm d \theta)$$

Mathematicians: "how are you supposed to integrate this expression doesn't make any sense!"

Theoretical physicists:
$$\int \sin(\mathrm d \theta)=\int \mathrm d \theta = 0$$
"Nice."

 

[DaveC426913]

I'm running errands for a friend's party in Owen Sound.

I'm at 16th Ave and 16th St, where they cross.

Do I tell her I'm at 1/8th Or 1/256th?

 

[collinsmark]

I'm running errands for a friend's party in Owen Sound.

I'm at 16th Ave and 16th St, where they cross.

Do I tell her I'm at 1/8th Or 1/256th?

The cross product of perpendicular streets is their simple product, assuming the streets are truly perpendicular. But the cross product is also a vector that is perpendicular to both streets. So I guess that would make it 256th in the up/down direction. Like an elevator. 256th floor or somesuch.

 

[berkeman]

 

[jack action]

 

[DaveC426913]

This isn't bad; this is danged clever.

 

[DaveC426913]

 

[pines-demon]

View attachment 363481

You ran a code for this?

 

[Borg]

You ran a code for this?

4! and 5! were both correct.

 

[martinbn]

4! and 5! were both correct.

But the sentences are missing a period at the end. Or may be an exclamation mark!

 

[DaveC426913]

You ran a code for this?

 

[DaveC426913]

But the sentences are missing a period at the end. Or may be an exclamation mark!

This is the math thread, not the english punctuation thread.

 

[pines-demon]

But the sentences are missing a period at the end. Or may be an exclamation mark!

I was wondering if we could find more examples of $n-m/k = p!$ for $n,m,k,p\in\mathbb{N}$.

 

[Ibix]

I was wondering if we could find more examples of $n-m/k = p!$ for $n,m,k,p\in\mathbb{N}$.

They also need to satisfy $(n-m)/k=p$ for the gag to work.

 

[pines-demon]

They also need to satisfy $(n-m)/k=p$ for the gag to work.

Are you telling me that it can be read in two ways?! (sarcasm)

 

[Ibix]

Are you telling me that it can be read in two ways?! (sarcasm)

Momentary humour detector failure, sorry.

I think "I was wondering if we could find more examples of $n,m,k,p\in\mathbb{N}$ that satisfy $n-m/k = p!$" would work better, though. <Waits for DaveC to remind that it's not the punctuation thread.>

 

[pines-demon]

I wrote some simple code:

import math


def find_joke_solutions(max_d, max_val):
    solutions = []
    for d in range(3, max_d + 1):
      fact=math.factorial(d)
      for c in range(2, fact//d):  # ensure c != 1
          for bi in range(1,max_val//c+1):
            b=bi*c
            # first equation: a = c*d + b
            a = c * d + b
                # second equation: a - (b/c) == fact
            if a - (b / c) == fact:
              solutions.append((a, b, c, d))
    return solutions

I got
$$a-b/c=d!$$
with $(a,b,c,d!)$:

• 25,5,5,4! (original case)
• 230, 220, 2, 5! (second case posted above)
• 721, 103, 103, 6!
• 5752, 5696, 8, 7!
• 45351, 45279, 9, 8!
• 362894, 220892, 15778, 9!
• 3629032, 3479072, 14996, 10!

I skipped those that had the same factorial result. You can prove that there is no solution for $d<4$ and $c>1$. Also it is interesting that for it to work $a,b$ have to be of the order of $d!$.

 

[berkeman]

 

[berkeman]

 

[BillTre]

Shouldn't it be veloci (raptors cancel)?

 

[Ibix]

Shouldn't it be veloci (raptors cancel)?

There was another raptor hiding in the bushes, just like in the film.

 

[jack action]

6 was scared of 7 because 7, 8, 9. But why did 7 ate 9?

Spoiler: Answer

Because you are supposed to eat 3 squared meals a day.

 

[jack action]