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\(\sum_{n=1}^{15} (2n-1)\)

 Apr 26, 2019
 #1
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+2

First term  = 2(1) - 1  = 1

15th term  = 2(15) - 1  = 29

 

Sum  =  [ first term +last term ] * number of terms  / 2  = 

 

 [ 1 + 29 ] * 15 / 2  =

 

[30] * 15  / 2   =

 

450  / 2  =

 

225

 

 

cool cool cool

 Apr 26, 2019

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