- Cuchulainn
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[$]\frac{dU}{dt} = \sum\limits_ {i=1}^n A_i U[$] (1)

or even

[$]\frac{\partial U}{\partial t} = \sum\limits_ {i=1}^n A_i U[$] (2)

[$]\frac{dU}{dt} = \sum_ {i=1}^n A_i U[$] (3)

or even

[$]\frac{\partial U}{\partial t} = \sum\limits_ {i=1}^n A_i U[$] (2)

[$]\frac{dU}{dt} = \sum_ {i=1}^n A_i U[$] (3)

Last edited by Cuchulainn on March 8th, 2018, 9:01 pm, edited 4 times in total.

I was wondering what "\ limits" does, but it seems it puts the limits directly below and above the Sigma rather than to the right

- Cuchulainn
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Yes. I find form (1) more compact and is probably less error-prone when proof-reading and mapping to code (just a feeling).I was wondering what "\ limits" does, but it seems it puts the limits directly below and above the Sigma rather than to the right

[$]\frac{dU}{dt} = \sum_ {i=1}^n A_i U[$] (3)

Einstein had his own summation notation

[$]\frac{dU}{dt} = A_i U[$] (4)

but I suppose we all can't be Einstein so stick to the long-winded (but 100% unambiguous) version.

- Cuchulainn
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[$]\mid x \mid[$]

[$]|x |^{2}[$]

Seems a bit long-winded.

[$]|x |^{2}[$]

Seems a bit long-winded.

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