
Mark M. answered 12/18/20
Mathematics Teacher - NCLB Highly Qualified
1.
Demonstrate true for n = 1
1 / (1(1 + 1) = 1 / (n + 1)
1 / 2 = 1 / 2
2.
Assume true for "n"
1 / (n(n + 1) = n / (n + 1)
3.
Demonstrate true for "n + 1"
[1 / (n(n + 1)] + [1 / (n + 1)(n + 1 + 1)] = [n / (n + 1)] + [1 / (n + 1)(n + 1 + 1)]
Simplifying the right side
[n / (n + 1)] + [1 / (n + 1)(n + 1 + 1)]
[n / (n + 1)] + [1 / (n + 1)(n + 2)]
[n(n + 2) + 1] / (n + 1)(n + 1 + 1)]
[n2 + 2n + 1] / (n + 1)(n + 1 + 1)
(n + 1)2 / (n + 1)(n + 1 + 1)
(n + 1) / (n + 1) + 1
QED