Question

which term of ap 121 113 117 is first negative term?​

Answer 1

General term or nth term of A.P

The general term or nth term of A.P is given by an = a + (n – 1)d,

where a is the first term, d is the common difference and n is the number of term.

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Solution:

Given:first term(a)= 121 

common difference (d)= 117- 121 = -4

∵ n th term of an AP

an = a + (n – 1)d

⇒121+(n-1) ×(-4)

⇒121-4n+4

⇒12+4-4n

⇒125 -4n

an= 125 -4n

For first negative term , an <0

⇒ 125-4n<0

⇒125<4n

⇒4n>125

⇒n>125/4

⇒n> 31 1/4

least integral value of n= 32

Hence, 32nd term of the given AP is the first negative term. 

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Hope this will help you...

Answer 2

Answer:

Refers to the attachment