Question

The first term of an arithmetic sequence is 2 and common difference is 4.
a) the sum of first ten terms of this sequence

Answer 1

Answer:

200

Explanation:

as we know the formula.. n/2*(2a+(n-1)d)

by applying it we get 200

Answer 2

Answer:

as per formula n= 10 , a= 2 ,d=4 , Sn =n+(n+1)/2 , 10/2(2×2+(10-1)4)=5(4+(9×4))=5×40 =200