I try to figure out how to work things with problems with answers in the back of the book so heres an example:
8,20,32,44......., n = 10
the answer was:
620
I tried the sum of a finite arithmetic sequence formula:
S{n}=n/2(a{1} +a{2}]
ended up getting 160... or something
**Numbers in {x} here are under the number like exponents but at the bottom if you understand? xD
Thanks if you can help! :)
8,20,32,44......., n = 10
the answer was:
620
I tried the sum of a finite arithmetic sequence formula:
S{n}=n/2(a{1} +a{2}]
ended up getting 160... or something
**Numbers in {x} here are under the number like exponents but at the bottom if you understand? xD
Thanks if you can help! :)

Good question!
To make learning math a bit easier, Dr. Pan (TucsonMathDoc) has recorded a YouTube video to help visually answer it.
Please comment on YouTube or Y!A and let her know if it helped.
Thanks!
To make learning math a bit easier, Dr. Pan (TucsonMathDoc) has recorded a YouTube video to help visually answer it.
Please comment on YouTube or Y!A and let her know if it helped.
Thanks!

S_n = n/2 [a1 + an ] or n/2[2a + (n1)d ]
since you know a = 8, d = 20  8 = 12 and n = 10, use second formula
S_n = 10/2 [2*8 + 9*12]
= 5(16 + 108)
= 5*124
= 620
since you know a = 8, d = 20  8 = 12 and n = 10, use second formula
S_n = 10/2 [2*8 + 9*12]
= 5(16 + 108)
= 5*124
= 620