Question

10 .find the partial sum S10 of the arithmetic series with a1 = 4, d = 5.

Answer 1

S10 = 320

Explanation:

The formula for calculating the sum of the nth term of an AP is expressed as

Sn = n/2(2a+(n-1)d))

Given

a = 4

d = 5

n = 10

S10 =10/2{2(5)+(10-1)5}

S10 =5{10+9(6)}

S10 =5{10+54}

S10 = 5(64)

S10 = 320

Hence the sum of the first ten terms of the sequence is 320