If 100 times the 100th term of an AP with non zero common difference equals the 50 times its 50th term, then the 150th term of this AP is :
100 (a + 99d) = 50 (a + 49d)
a + 149d = 0 .......(A)
and
T150 = a + 149d = 0 [From (A)].
We are given that for an arithmetic progression (AP) with non-zero common difference, 100 times the 100th term equals 50 times the 50th term. We need to find the 150th term.
The nth term of an AP with first term and common difference is given by:
According to the problem:
Substituting the formula for the nth term:
Simplifying the expressions inside the brackets:
Divide both sides by 50 to simplify:
Expanding both sides:
Bring all terms to one side:
The 150th term is given by:
But from the previous step, we have . Therefore:
The 150th term of this AP is zero.
An arithmetic progression is a sequence of numbers in which the difference between consecutive terms is constant. This difference is called the common difference ().
A useful property is that for any three consecutive terms, the middle term is the average of the other two. For example, for terms , we have . This problem is a specific application of such a property.