Question

31st question... step by step explanation​

Answer 1

Answer:

Let a be the first term and d be the common difference of the given A.P.

Given;

a7 = 1/9 and   a9 = 1/7

a7 = a +(7 - 1) d   

[an = a + (n - 1)d]

a7 = a + 6d

1/9 = a +6d ………………(1)

a9 = a +(9- 1) d

[an = a + (n - 1)d]

a9 = a + 8d

1/7 = a+ 8d……………….(2)

Subtracting equation 2 from equation 1,

1/9 - 1/7 = a- a +6d -8d

(7 - 9)/63 = - 2d

-2 = -2d × 63

d = -2 /(-2×63)

d = 1/ 63

d =  1/ 63

Put the value of d in eq 1

1/9 = a + 6d

1/9 = a + 6 × (1/ 63)

1/9 = a + 6/63

1/9 - 6/63  =a

(7 -6 )/ 63 = a

1 /63 = a

a63 = a +62d

a63 = 1/63  + 62 × (1/63)

a63 = 1/63 +62/63

a63 = (1+62)/63

a63 = 63 / 63

a63 = 1

Hence, the value of 63rd term is 1.

Answer 2

Answer:

1 is 63rd term

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Step-by-step explanation:

refer to attach image