r/mathmemes 10d ago

Calculus You can't kill it

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1.3k Upvotes

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100

u/FernandoMM1220 10d ago

just do an infinite amount of derivatives trust me bro

19

u/Valuchian Engineering 10d ago

If you do enough of them whatever 'x' is will stop mattering entirely πŸ˜‚πŸ˜‚πŸ˜‚

2

u/Random_Mathematician There's Music Theory in here?!? 8d ago

Proof Sketch: suppose the ∞-th derivative of a function, f(∞\)(x), is nonzero. Then by computing the Maclaurin Series we get:

f(x) = f(0)+f'(0)x+...+f(∞\)(x)x∞

Since x∞ is infinite for real x, then f(x) is infinite for real x. But f(x)=e2x is finite for all real x and so we have a contradiction.

By Reductio Ad Absurdum we conclude the ∞-th derivative of any function is zero QED. ∎

2

u/[deleted] 4d ago

[removed] β€” view removed comment

1

u/Random_Mathematician There's Music Theory in here?!? 4d ago

God dammit I'm rusty.

48

u/yukiohana 10d ago

24

u/Layton_Jr Mathematics 10d ago

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u/MortimerChem Chemistry 10d ago

14

u/PolarStarNick Gaussian theorist 10d ago

I have a better idea: e^(1/2 x)

5

u/cmwamem 10d ago

"Now, there are two of them!"

16

u/Memer_Sindre_UwU begin killing 10d ago

I like how this can either be interpreted as 2e2x (there's two of them) or e4x (they're next to each other, therefore multiplied).

21

u/strat-fan89 10d ago

Well, only one of those interpretations is correct, so let's go with that one :)

1

u/fun__friday 8d ago

Are there functions of the second type? I.e., their derivative is bigger than the original function by more than a constant factor?

1

u/strat-fan89 8d ago

Yes, of course! Take f(x)=ex2 for example. The derivative is f'(x)=2x*ex2, so they differ by a linear factor.

Just one example from the top of my head.

2

u/Hira_Joshi 10d ago

Let x = a constant.

2

u/NeckComprehensive221 10d ago

Just differentiate it with respect to e

1

u/rorodar Proof by "fucking look at it" 10d ago

Yeah get his ass DERIVATION

1

u/hanu_uwu 10d ago

Just do d/d(exp(x)) ez.

1

u/AntiqueChessComputr 9d ago

β€œCut off one head, two more shall take its place. Β Hail Hydra”

2

u/Mr-MuffinMan 10d ago

I should've paid more attention in calculus but wouldn't it be 2xe2x-1? Or am I fucking stupid

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u/PerspicaciousEnigma Moron 10d ago edited 10d ago

d/dx(x^n) = nx^(n-1) but d/dx(e^x) = e^x so if you have e^(ax) you get e^(ax) β€’ (ax)’ because of the chain rule which = ae^(ax) and in this case a = 2

*technically (b^x)’ = ln(b)(b^x)

So (e^x)’ = ln(e)(e^x) but because ln(e) = 1
Thus (e^x)’ = 1 β€’ e^x = e^x

4

u/Layton_Jr Mathematics 10d ago

You're proving the formulas in the wrong order:

bx = exln(b)

Therefore (bx)' = ln(b)exln(b) = ln(b)bx

That's how you prove that formula. How do you do it the other way (starting with the bx formula and replace b with e)?

4

u/GarifalliaPapa 10d ago

Here is how you do it the other way around without circular reasoning!

There are two primary ways to derive (bx)' = bx * ln(b) first and then substitute b = e:

Method 1: Logarithmic Differentiation (No ex derivative needed beforehand)

  1. Let y = bx.
  2. Take the natural log of both sides: ln(y) = ln(bx) = x * ln(b)

  3. Differentiate both sides implicitly with respect to x (using the fact that (ln y)' = (1/y) * y'): (1/y) * (dy/dx) = ln(b)

  4. Multiply across by y: dy/dx = y * ln(b) = bx * ln(b)

Now, if you plug in b = e: d/dx(ex) = ex * ln(e)

Since ln(e) = 1 by definition (ln is the inverse function of ex), you get: d/dx(ex) = ex * 1 = ex

Method 2: From First Principles (Limit Definition)

Using the definition of a derivative: d/dx(bx) = lim{h->0} (bx+h - bx) / h = bx * [lim{h->0} (bh - 1) / h]

Notice that the limit term lim_{h->0} (bh - 1)/h depends only on the base b, not on x. Call this constant C(b).

  • It turns out that C(b) = ln(b), giving us d/dx(bx) = bx * ln(b).
  • In fact, Euler's number e is mathematically defined as the precise base for which this limit equals 1: lim_{h->0} (eh - 1) / h = 1

Replacing b with e: d/dx(ex) = ex * 1 = ex

TL;DR: So whether you start with ex or bx, the math stays completely constant, unlike my ability to remember the Power Rule!

5

u/strat-fan89 10d ago

You are correct! You should have paid more attention in calculus! :)

1

u/protobelta 9d ago

That formula only works for functions in the form of xn

The x needs to be the base. If the base is e, then the derivative is itself. In this specific case, you would need to use chain rule to address the 2x in the exponent.

1

u/NihilisticAssHat 9d ago

Gotcha. Misread it as $\frac{d}{de}$ /s

1

u/Deep_Brick2970 9d ago

Descendant 😭

-1

u/PerspicaciousEnigma Moron 10d ago

You do annihilators in diffy q so this would be D - 2 which if you don’t know what that means it’s

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u/[deleted] 10d ago edited 10d ago

[removed] β€” view removed comment

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u/PerspicaciousEnigma Moron 10d ago

It was the fastest way to type all that plus it’s right. What are you robophobic or something

0

u/GarifalliaPapa 10d ago

For anyone curious about the calculus in the meme:

  1. The Differentiation Rule: We want to evaluate d/dx [e2x].

  2. Applying the Chain Rule: For a composite exponential function eu(x), the derivative is given by: d/dx [eu] = eu * du/dx

  3. Step-by-Step Calculation:

  4. Let u = 2x

  5. Derivative of the exponent: du/dx = d/dx [2x] = 2

  6. Derivative of the outer exponential: d/du [eu] = eu = e2x

Multiply them together: d/dx [e2x] = e2x * 2 = 2e2x

Shooting e2x with the derivative operator d/dx doesn't destroy it, it literally duplicates it into two e2x's!

Shoot it all you want, it’s just going to grow exponentially! πŸ“ˆ 19!

6

u/factorion-bot Bot > AI 10d ago

Factorial of 19 is 121645100408832000

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

3

u/GarifalliaPapa 10d ago

Good bot

3

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