What is the proof of d(x2)/dx = x?

[Ursole]

d(x^2)/dx = x

d(x²)/dx = x

PROOF:

d(x²)/dx = d(x + x + x + ... (x times))/dx

= d[x]/dx + d[x]/dx + d[x]/dx... (x times)

= 1 + 1 + 1 + ... (x times)

= x

QED

 

[arildno]

\frac{d}{dx}\sum_{i=1}^{x}x=(\frac{d}{dx}\sum_{i=1}^{x}1)x+\sum_{i=1}^{x}\frac{dx}{dx}=x+x=2x

 

[Pattielli]

d(x²)/dx = x

PROOF:

d(x²)/dx = d(x + x + x + ... (x times))/dx

= d[x]/dx + d[x]/dx + d[x]/dx... (x times)

= 1 + 1 + 1 + ... (x times)

= x

QED

What a new invention ! <<:thumbsUp:>>

 

[gnome]

Isn't this silliness getting old yet?

https://www.physicsforums.com/showthread.php?t=8316