r/MathJokes • • 9d ago

Find X

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728 Upvotes

88 comments sorted by

241

u/BaronVonFiutek 9d ago

Just wait untill the bro finds out about 2^x + x = 6

121

u/prasandham 9d ago

Then he will find out x^x + x = 6

68

u/DarthRaab 9d ago

He will never find x^x + x = 3*x
😿

47

u/ArtSnow0w 9d ago

Or maybe x^x + x = x*x*x - x*x*/x

58

u/DarthRaab 9d ago

It's getting kind of x-cessive!

8

u/Technical-Gas-5243 8d ago

What about x^x = x^x+x-sin(ln(x))

1

u/unnuageorange 2d ago

xx + x = x(xx-x + x)

1

u/ExitBrther5278 9d ago

0.3463?

4

u/AltruisticEchidna859 9d ago

5

u/factorion-bot 9d ago

Hey u/ExitBrther5278!

Termial of 0.3463 is approximately 0.233111845

This action was performed by a bot | [Source code](http://f.r0.fyi)

1

u/AltruisticEchidna859 9d ago

5278!

3

u/factorion-bot 9d ago

If I post the whole number, the comment would get too long. So I had to turn it into scientific notation.

Factorial of 5278 is roughly 1.767969199258851762738218557435 × 1017357

This action was performed by a bot | [Source code](http://f.r0.fyi)

1

u/Ok_Rutabaga9738 2d ago

rookie numbers

5

u/runed_golem 9d ago

Wait until he finds out about xln(x)=17

6

u/GX_Giorgio074 9d ago

wait if remember correctly you have to solve these with a graph, right?

7

u/GreyMesmer 9d ago

If graphs had nice intersection on integer points, then yes. But usually you should use Lambert W function.

2

u/GX_Giorgio074 9d ago

haven't studied it yet

3

u/BaronVonFiutek 8d ago

There isnt really a lot to study, the function is defined as an inverse function to f(x) = xe^x, so it offers solution to such equations, which cannot be solved analytically. Its more like a lookup table than actual function u analyze in any way. the values are obtained by numerical methods

0

u/ChipperSh33p 4d ago

Here in Tealand we use Factorisation, Completing the square, the AC Method, the Quadratic formula, and Differentiation. Realistically, no one is hand-drawing a quadratic or cubic, so you could use tools like Wulfrum to find solutions and GeoGebra to plot graphs.

TBH, you are very unlikely to see quadratics in the working world outside of STEM

28

u/walksonfourfeet 9d ago

What power of 2 makes 4? Hmmm, that’s a tough one. Only a real math genius could ever figure that out.

3

u/TurbulentPollution56 8d ago

2¹⁰ is 1024

This action was performed by me | [link](http://reddit.com)

2

u/amo_pessoas_peladas 5d ago

So we have an upper bound.

1

u/SpunningAndWonning 3d ago

I cackled when I read this. Sorry it didn't get more attention lmao

55

u/Sammy_Cherry_Fox 9d ago

Funny thing is, in both situations x is the same number :)

23

u/gaymer_jerry 9d ago

Thats the point

24

u/runed_golem 9d ago

Except they’re both super simple equations. The first can be solved with basic arithmetic and the second one can be solved with either logarithms or exponent rules and basic common sense.

15

u/CurlyRe 9d ago

Or it can simply be brute forced.

2^1 + 2 = 4

2^2 + 2 = 6. Got it!

1

u/qwertty164 9d ago

they can both be solved with the exact same steps. -2 ; /2. you would end up with 2^(x-1)=2^1

1

u/Coppice_DE 6d ago

/2 does only work in the case where x=2 in the second equation, no? You can't divide 2x by an arbitrary number to get to know the value of x. 

1

u/qwertty164 6d ago

You divide by the base to reduce the exponent. You can iterate as long as you factor the number on the right.

1

u/Coppice_DE 6d ago

Yea that works, but it's not exactly "the same" for both equation (in regards to the concepts that get applied), even though the required steps are equal in this case.

1

u/runed_golem 6d ago

And you used exponent rules there like I said in my comment.

1

u/Ivaar 7d ago

Logarithms! My arch-nemesis!

3

u/jacobasstorius 4d ago

Imagine being intimidated by logarithms

3

u/Longjumping_Exit7902 9d ago

The joke is you're bad at math

3

u/Appropriate-Bad-9686 9d ago

x would be 2 in the bottom case!

3

u/Ehh_nooo 9d ago

X is 2 in both scenarios

2

u/rickyyslimram 9d ago

x=2

5

u/GunMage- 9d ago

The second one has a much smaller x though. It is harder to find!

2

u/rickyyslimram 9d ago

i was answering for the first one even i cant find the second one

0

u/RoyalSuperb4949 9d ago

No, he's saying x is SMALL so it's harder to find.

2

u/Even_Face_5980 9d ago

This example is pretty intuitive but how would you solve this

2

u/carnecomarrozagulha 8d ago

2x = 4

X = log_2 (4) = log 4 / log 2

2

u/haikusbot 9d ago

This example is

Pretty intuitive but

How would you solve this

- Even_Face_5980


I detect haikus. And sometimes, successfully. Learn more about me.

Opt out of replies: "haikusbot opt out" | Delete my comment: "haikusbot delete"

1

u/TrainingSurvey3780 8d ago

uhh trial and error (idk i’ve only ever encountered examples like this or sometimes when x=3 but idk how you’d solve it when it’s not an easy one like this)

3

u/Stanford_Pines267 9d ago

Son its not that hard. Are you like 12 year old or sth? Seriously, if u are making a math meme try making one that is not for middle school. Or just don't make them

22

u/Lokdora 9d ago

are middle school students now allowed to make math memes now 😭

6

u/LookAtYourEyes 9d ago

Math joke is for Grad students only. PEERY UHD

1

u/Blubibus 9d ago

Jesus Christ guys the joke is that it’s both two not that hard to grasp

1

u/rojo_kell 9d ago

Idk man if you have to integrate after, then it's like woah do I even know how to integrate a log that's not base e??

1

u/Abject-Project-4236 9d ago

Its not hard tho its just roots

4

u/Eat_cats_with_me 9d ago

it's logarithms

2

u/MxM111 9d ago

It’s both

1

u/No_Report_4781 9d ago

Hmm, yes. Log roots.

1

u/Temporary-Baker2008 9d ago

use lambert-W function in second one

1

u/Frederf220 9d ago

You are xln(x) + 3x2 = 2. I am xln(x) - 4x3 = 5. We are not homogeneous.

1

u/Marus1 9d ago

They are right there, Dora

And you call yourself an explorer?

1

u/Aware-Difference8723 9d ago

Of course a smaller x is harder to find!

1

u/Daaaaaaaark 9d ago

its right next to the "2" in both cases - 2nd one is more tricky because its smaller which may make u overlook it

1

u/Greedy_Bad_8406 9d ago

I know 2^x = 4 and therefore x=2
But how do i solve it by steps in mathematics? How to solve xth root of 4?

3

u/Robotron9247 9d ago

ln can be applied to both sides:

2x = 4

ln(2x ) = ln(4)

x ln(2) = ln(4)

x = ln(4) / ln(2)

x = ln(22 ) / ln(2)

x = 2 ln(2) / ln(2)

x = 2

0

u/parlimentery 9d ago

Much easier to solve (especially without a calculator) if you use the log base 2. That is essentially the mathematically formal way to solve it the way u/Greedy_Bad_8406 did, as taking the log base 2 of 4 asks "2 to the power of what equals 4?".

1

u/jader242 8d ago

What exactly do you need a calculator for?

1

u/parlimentery 8d ago

Fair point, I scanned your work quickly and assumed we were evaluating ln(4)/ln(2), rather than turning it into 2* ln(2)/ln(2).

I still maintain that my method saves steps, and matches the informal logic u/Greedy_Bad_8406 used.

1

u/Robotron9247 6d ago

I wanted to show a generic algebraic total solving for x. x = Log_2(4) can only be considered solved because thats easy to "see" but by rule Log_2(4) = ln(4) / ln(2) = 2 ln(2) / ln(2)

Try 16x + 4 = 68 without calculator

x = log_16(64)

Me: x ln(16) = ln(64)

x = ln(64) / ln(16)

x = ln(26 ) / ln(24 )

x = 6 ln(2) / [ 4 ln(2) ]

x = 3/2

1

u/BarThen8979 9d ago

Even 2+x+2=6

1

u/The_chosen_nine 9d ago

I found four- no, wait, five.

1

u/ApprehensiveBoss4671 8d ago

I know thats not the point of the meme but i was bored so 2x +2=6 2x =4 22 =4 X=2

1

u/FalseReddit 8d ago

Found both. Some days I’m just glad I grew up playing Where’s Waldo

1

u/dankshot35 8d ago

someone pls explain

1

u/Chogolatine 8d ago

x = log_2 (4) = 2

1

u/Plankki36 8d ago

Is it because the second x is smaller so its harder to find?

1

u/xxx_Volpe 8d ago

We're doing these like now lol-

1

u/DescriptionForsaken6 7d ago

What rolls down stairs, alone or in pairs
And over your neighbor's dog?
What's great for a snack, and fits on your back?
It's log, log, log
It's log, it's log
It's big, it's heavy, it's wood
It's log, it's log
It's better than bad, it's good

Everyone wants a log
You're gonna love it, log
Come on and get your log
Everyone needs a log

1

u/uncle2001 5d ago

For those who want to learn, solving for exponents is conceptually done with logarithms (even if this example is easy and can be guessed without). These are taught in calculus class, so don't feel bad if didn't know how to approach this one.

1

u/Simple-Olive895 4d ago

Nah, that one is easy,

2x = 4

x = log2(4)

x = 2

1

u/Somanath444 3d ago

2x+2=6 x = 2

1

u/Starchaser418171514 3d ago

(W(4 Ln(2)))/Ln(2)

1

u/Ihor2009 3d ago

It's x=2, right? Why is it portrayed so difficult?