## Double derivative [ENDORSED]

$H_{\psi }=E_{\psi }$

1-D: $E_{TOTAL}\psi (x)=E_{k}\psi (x)+V(x)\psi(x)=-\frac{h^{2}}{8\pi ^{2}m}\frac{d^{2}\psi(x)}{dx^{2}}+V(x)\psi(x)$

Ruohan Sun 3I
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Joined: Fri Sep 29, 2017 7:07 am

### Double derivative

What does double derivative mean?

Dylan Davisson 2B
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### Re: Double derivative  [ENDORSED]

A double derivative would be the derivative of the derivative of a function. So, it's basically telling you the rate of change that something is changing.

For example, for a function of displacement, velocity would be its derivative (change of displacement over time), and acceleration would be its double derivative (change of velocity over time).

I don't know the context for this question, but I hope this helps a little.

Hellen Truong 2J
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### Re: Double derivative

For the wave function, the double derivative helps you understand how either side is related to each other. Because psi is returned on the right side after the equation is performed, you can relate this concept to the way (for example) sinx would return -sinx after you derive it twice. Though the original sinx and the new -sinx are opposite in sign, the original function still comes back, similar to how it does in Schrodinger's equation.

Minie 1G
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Joined: Fri Sep 29, 2017 7:04 am

### Re: Double derivative

A double derivative is the same as a second derivative. Find the derivative of your function. Then, take another derivative -> you now have a double derivative.