+0  
 
0
84
1
avatar

For 5 + 16 + 27 + 38 + ..., find the sum of the first n terms, as a function of n.

 May 14, 2020

Best Answer 

 #1
avatar+21953 
+1

Each of the terms of the series  5 + 16 + 27 + 38 + ...

can be determined by this formula:  11n - 6  where n is the number of the term.

 

The formula for the sum of an arithmetic series is:  Sum  =  n·(first + last) / 2

 

n  is the number of terms

the first term is 5

the last term is 11n - 6

so:     Sum  =  n·[ 5 + (11n - 6) ] / 2  

                    =  n·[ 5 + 11n - 6 ] / 2  

                    =  n·[ 11n - 1 ] / 2  

 May 14, 2020
 #1
avatar+21953 
+1
Best Answer

Each of the terms of the series  5 + 16 + 27 + 38 + ...

can be determined by this formula:  11n - 6  where n is the number of the term.

 

The formula for the sum of an arithmetic series is:  Sum  =  n·(first + last) / 2

 

n  is the number of terms

the first term is 5

the last term is 11n - 6

so:     Sum  =  n·[ 5 + (11n - 6) ] / 2  

                    =  n·[ 5 + 11n - 6 ] / 2  

                    =  n·[ 11n - 1 ] / 2  

geno3141 May 14, 2020

61 Online Users

avatar
avatar
avatar
avatar