Hi,

Re TY, one may use either of the 2 formulas*** to find the sum

3, 7, 11, 15, 19...,   Arithmetic sequence, d = 4

For sums of an arithmetic sequence one can use:

***  OR

***



  |Using the Latter after finding 

  ⇒    

 

RELATED QUESTIONS

Sequence: 3, -6, 12, -24, 48,..., find S(sub 20). If S(sub 0)= 3.  Then find the sum... (answered by ewatrrr)

Please help me out in this sequence of finding r! Thank you so much! 

Find r given... (answered by stanbon)

The system of linear equations has an unique solution. Find the solution using Gaussian... (answered by AnlytcPhil)

In the arithmetic sequence: a(sub 5) =0, and a(sub 25) =8. What is a(sub 2)?

Thank you  (answered by ewatrrr)

I've been having some problems acquiring a formula for finding how much of an object... (answered by stanbon,Alan3354)

Hello! In this problem, I had some trouble: "Find the value of t(subscript 2) + t(sub3) +  (answered by Edwin McCravy,Fombitz)

Find t sub n if t sub 3 is equal to 15 and t sub 8 is equal to... (answered by Edwin McCravy)

Hi! Could you please help me out in this problem! Thank you so much, and for your... (answered by stanbon)

Find a decimal approx for S (sub 15) in the geometric sequence with first term 83 and... (answered by ewatrrr)