Question

find the sum of 2-1/2+1/8-......

Answer 1

Answer:

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

= n/2 (2 + n-1(1.5))

= n/2 (2 + 1.5n - 1.5)

= n/2x2 + n/2(1.5n) -n/2(1.5)

= n + 1.5n²/2 - 1.5n/2