Question

Find the first negative term of sequence 999, 995, 991, 987, ...

Answer 1

Answer:

983

Step-by-step explanation:

999-995=4,995-991=4,991-987=4,987-a=4.Thus a=983.The number after 987 is 983

Answer 2

Answer

251st term, - 1

Explanation

Given A.P., 999, 995, 991, 987 ...

To find the first negative term.

here, a = 999

d = - 4

We will check first whether 0 is a term of this A.P. or not

Apply the formula for general term

$\sf T_n = a + (n - 1)d$

$\sf 0 = 999 + (n - 1)(-4) \\\\\sf \implies - 999 = (n - 1)(-4) \\\\\implies n - 1 = \frac{-999}{-4}\\\\\implies n - 1 = 249.75\\\\\ \implies n = 250.75$

Since n is in decimal form, this means that 0 is not the term of this A.P. Now, the first negative term of this would be the natural number just greater than our value of n.

Our value of n = 250.75

hence, first negative term would be the 251st term of this A.P.

When we put the value 251 in our formula of general term, we get -1. -1 is the first negative term of this A.P.