Question

which term of the sequence 36, 34.5, 33, 31.5,........ is the first negative term

Answer 1

Given AP is 36,34.5,33,...

Let a be the first term and d be the common difference.

= > a = 36

= > d =34.5 - 36 = -1.5

Here, an < 0

= > a + (n - 1) * d < 0

= > 36 + (n - 1) * (-1.5) < 0

= > (n - 1) - (1.5) < -36

= > (n - 1) > 36/1.5

= > (n - 1) > 24

= > n > 25.

Therefore, the 1st negative term is 26.

Hope this helps!