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Im having trouble with summation notation. I dont know how to find the value of a certain variable for example. 

 

 This is giving me lots of trouble and I have no idea what to do.

 

If you could help me figure out what to do that would be great.

 

Thank you.

 Sep 1, 2015

Best Answer 

 #1
avatar+250 
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At the bottom of the summation it indicates what it starts on, in this case i starts on 1. At the top of the summation it tells you what the maximum number is that i gets up to. Now you need to sum every number from what you start on up till the maximum.

 

Your 1st sum translates to $$x_1+x_2+x_3+x_4+x_5+x_6=15$$Your 2nd sum translates to $$x_1+x_2+x_3+x_4+x_5=20$$Your 3rd sum translates to $$\frac{x_1+x_2+x_3+x_4+x_5+x_6+x_7}{7}=8$$

 

Hope you should be able to do the rest of the problem now =)

 Sep 2, 2015
 #1
avatar+250 
+8
Best Answer

At the bottom of the summation it indicates what it starts on, in this case i starts on 1. At the top of the summation it tells you what the maximum number is that i gets up to. Now you need to sum every number from what you start on up till the maximum.

 

Your 1st sum translates to $$x_1+x_2+x_3+x_4+x_5+x_6=15$$Your 2nd sum translates to $$x_1+x_2+x_3+x_4+x_5=20$$Your 3rd sum translates to $$\frac{x_1+x_2+x_3+x_4+x_5+x_6+x_7}{7}=8$$

 

Hope you should be able to do the rest of the problem now =)

Brodudedoodebrodude Sep 2, 2015

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