Question

If the seventh term is 1/7 and 9th term is 1/7 find the 63rd termt

Answer 1

Answer:

Did you mean If seventh term of AP is 1/9 and it 's ninth term is 1/7 find its 63rd term?

Step-by-step explanation:

nth term = a+ ( n-1 ) d

( where a is the first term, n is the no. of terms

and d is the difference between two consecutive terms . )

seventh term = a7 = 1/9

ninth term = a9 =1/7

a7 = a + 6d - ( 1 )

a9= a+ 8d - ( 2 )

by subtracting ( 1 ) from ( 2 )

(+ )a+ 8d = 1/7 ( +)

( - )a+ 6d = 1/9 ( - )

= 2d = 2 /63

d = 1/63

by putting value of d in eq. ( 2 )

a + 8 ( 1/63 ) = 1/7

a + 8/63 = 1/7

a = 1/7 - 8/63

a = 1/63

a 63 = a + 62d

=1/63 + 62 ( 1 /63 )

= 1/63 + 62/63

= 1

Answer 2

a17=1/7

a+16d=1/7 ------(1)

a9=1/7

a+8d=1/7------(2)

(1)-(2)

8d=0

d=0

(2)==>a+8(0)=1/7

a=1/7

a63=1/7+62(0)

a63=1/7

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