Question

the 15 term of an AP is 3 more than twice it's 7 term it the 10 term of the AP is 41 then find its n term​

Answer 1

EXPLANATION.

15th term of an Ap is 3 more than twice it's 7 th

term.

10th term of an Ap = 41.

To find it's n terms.

Formula of N th term of an Ap.

=> An = a + ( n - 1 ) d

=> 15th term = 2 ( 7th term) + 3

=> a + 14d = 2 ( a + 6d ) + 3

=> a + 14d = 2a + 12d + 3

=> 2a - a + 12d - 14d + 3 = 0

=> a - 2d = -3 .....(1)

10th term = 41

=> a + 9d = 41 .....(2)

From equation (1) and (2) we get,

=> - 11d = - 44

=> d = 4

put the value of d = 4 in equation (2) we get,

=> a + 9(4) = 41

=> a = 5

Therefore,

Nth term of an Ap

=> An = a + ( n - 1 ) d

=> 5 + ( n - 1 ) 4

=> 5 + 4n - 4

=> 4n + 1

Nth term of an Ap = 4n + 1.

Answer 2

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