Math, asked by prajulkrishnak, 8 months ago

Find nth term and 15th term of an arithmetic sequence 3,8,13,18​

Answers

Answered by kaushalyadav3132
2

Answer:

tn = a+(n-1)×d

t15 = 3+(n-1)×5

=3+(5n-5)

3+5n-2

t15 = 5n-1

t15 =5×15-1

75-1

t15 = 74

Answered by Anonymous
8

Given :

  • A.P. 3,8,13,18.....

To find :

  • the 15th term

Solution :

The given sequence is in A.P.

its first term a 3

d = 8 - 3

d = 5

t15 = ?

tn = a + (n -1)d

t15 = a + (15 - 1) d

t15 = 3 + 14 × 5

t15 = 3 + 70

t15 = 73

∴ 15th term is 73

Extra formula's :

  • t_n = a + ( n - 1 ) d
  • S_n = n/2 [ 2a + ( n - 1 ) d ]
  • S_n = n/2 ( a + 1 )
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