Question

The 1st negative term of an AP 356,349,342….

solve by process ​

Answer 1

Answer:

"12

Step-by-step explanation:

Here

First term (a) = 53

Common difference (d) = -5

Let nth term is the first negative term of the given AP.

Therefore,

nth term in AP

Tn= a + (n – 1) × d

Tn = 53 + (n -1) × (- 5)

Tn = 53 – 5n + 5

Tn = 53 + 5 – 5n

Tn = 58 – 5n

Now, we have to find the suitable value of n, so that the value of (58 – 5n) is negative.

Let us take n = 11

nth term = 58 – (5 × 11)

= 58 – 55

= 3 Which is not negative.

Then putting n = 12, we get.

nth term = 58 – (5 × 12)

= 58 – 60

= – 2

This is the first negative term of the series, and it is the 12th term of the AP.

So, n =12"

Answer 2

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135, 131, 127....

nth term of an AP= a + (n − 1)d

Here a = 135

d = 131-135= -4

135+ (n-1)(-4) <0

135 < 4n-4

4n > 139

n> 34.75

.. n = 35

a35 = a + 34d

= 135 + 34(-4)

= 135 136 = -1

. 35th term is its first negative term