Answer by Edwin McCravy(20056)   (Show Source): You can put this solution on YOUR website!
 Find the value of the following summation:


We write out the first few terms, and the last term:

[2(15)-5] + [2(16)-5)] + [2(17)-5] + [2(18)-5] + ... + [2(47)-5}

[30-5] + [32-5] + [34-5] + [36-5] + ... + [94-5]

25 + 27 + 29 + 31 + ... + 89

We see this is an arithmetic series, with a1 = 25,
d = 2, and an = 89

We first use the nth term formula to find n:















Then we use the sum formula:







Answer: 1881

Edwin
 

RELATED QUESTIONS

Please  sir  ,  send me the value or method to  find the value  of the following... (answered by psbhowmick)

use mathematical induction to prove the summation of 
i=1... (answered by KMST)

find the sum of the following arithmetic series and write in summation notation... (answered by MathLover1)

find the sum of the following arithmetic series and write in summation notation... (answered by MathLover1)

use mathematical induction to prove the summation formula:

{{{sum((4i-1),1=1,n)}}} =... (answered by Edwin McCravy)

Sum -(in summation notation)
 lower limit is i = 3 and upper limit is n of: 
(-3-4i) =... (answered by Edwin McCravy,AnlytcPhil)

Find the mean for the following. Round to the nearest tenth.

Value Frequency   
 (answered by Edwin McCravy)

Find the sum.

5/m^2n^2   +    m/n

 (answered by Alan3354)

Use the Binomial Theorem to express the following sum in closed form (without using a... (answered by ikleyn)