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avatar+246 

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
avatar+246 
+1

Oh wait, is this what it is?

 

 =

 Oct 19, 2020
 #2
avatar+111602 
+1

I just wrote a post explaining it and now it has disappeared.  sad

 

But what you have said is correct. 

 Oct 19, 2020
 #3
avatar+111602 
+1

The first one says square all the terms, then add them up.

 

the second one is the other way around.

Add up all the terms and square the answer.

 

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
 #4
avatar+246 
+1

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

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