Find the sum of the first fifty, one hundred, n terms of the sequence (Xn), if: Xn = n-4

Let’s start finding the sum of the first fifty terms of a sequence by recalling the formula for calculating the sum of n – the first members of an arithmetic progression. Since the given sequence xn = n – 4 is an arithmetic progression.

Sn = (a1 + an) / 2 * n.

We now turn to finding the first and fiftieth term of the progression.

n = 1;

x1 = 1 – 4 = -3;

n = 50;

x50 = 50 – 4 = 46.

It remains to substitute the values into the formula and calculate:

S50 = (-3 + 46) / 2 * 50 = 43 * 25 = 1075.