Use sigma notation to write the sum

Question

1/(3{2}) + 1/(4{3}) + ... + 1/(8{7})

Options:

a. Σ(from n=1 to 6) 1/(n+2)!

b. Σ(from n=0 to 5) 1/{(n+1)(n+2)}

c. Σ(from n=0 to 6) 1/{n(n+1)}

d. Σ(from n=1 to 4) 1/{(n+1)(n+2)}

e. Σ(from n=1 to 6) 1/{(n+1)(n+2)}

Answer 1

choice (e) works. If n = 1, you get 1 / {(2)(3)] and if n = 6, the result is 1 / [(7)(8)]. Another way to write the sum is to use 1 / [n(n+1)] with n varying from 2 to 7.