Question

What is the 100th triangular number?

Answer 1

`T_1_0_0=5050`

Explanation:

A triangular number is number that can be recomposed in the form of an equilateral triangle. Each triangular number is defined by:

`T_n=(n^2+n)/(2) \hspace{5} n\in N`

Hence, evaluating n=100

`T_1_0_0=((100)^(2)+100 )/(2) =5050`