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# What does this sign mean?

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I know I sound a little stupid by saying this, but in one of my textbooks, I saw this sign and I got all confused. What does it mean and how is it any different from the second one?

Image 1:

Image 2:

Oct 18, 2020

#1
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Oh wait, is this what it is?

=

Oct 19, 2020
#2
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I just wrote a post explaining it and now it has disappeared.

But what you have said is correct.

Oct 19, 2020
#3
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The first one says square all the terms, then add them up.

the second one is the other way around.

for example

$$\displaystyle{\sum_i^3}x_i^2=1^2+2^2+3^2=1+4+9=14\\~\\ \left(\displaystyle{\sum_i^3}x_i \right)^2=(1+2+3)^2=6^2=36$$

Oct 19, 2020
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Ok, thanks! I get what it is now. I saw you composing an answer and all of a sudden it stopped. I had a feeling you either went AFK or there was a glitch.

Nacirema  Oct 19, 2020