OpenStudy (anonymous):

What is the sum of the arithmetic sequence 4, 11, 18 …, if there are 26 terms?

5 years ago
hartnn (hartnn):

the formula for sum of 'n' terms of Arith seq is (n/2)*(2a+(n-1)d) a is the 1st term d is the common difference,here d=7 just put values and calculate

5 years ago
OpenStudy (anonymous):

I have to do taht 26 times:?

5 years ago
hartnn (hartnn):

no!! u just put the value of n as 26,a as 4 and d as 7 and that will give u sum of 26 terms directly...

5 years ago
OpenStudy (anonymous):

Can you show me

5 years ago
hartnn (hartnn):

yup ... (26/2)*(2*4+25*7) =13*(8+175) can u solve further?

5 years ago
OpenStudy (anonymous):

No

5 years ago
OpenStudy (anonymous):

2,379 ?

5 years ago
OpenStudy (anonymous):

@hartnn

5 years ago
hartnn (hartnn):

yes :)

5 years ago