Question

a=7 तथा a13=35 दिया गया हो तो d और s13 गयात कीजिए

Answer 1

HEYA!!
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Arithmetic Progressions :-
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A [ First term ] = 7

A13 = 35

A + 12 d = 35

7 + 12d = 35

12d = 28

d=2

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S13 = 13/2 { 14 + 12×2}

= 13/2 { 14 + 24 ]

13/2 × 38

19× 13

=247.

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Answer 2

Answer:

d = 7/3, Sn=273

Step-by-step explanation:

First term of an AP = a = 7

Thirteenth term of an AP = 35

a + 12d = 35 ------(1)

Substitute a in eq - (1)

a + 12d = 35

(7) + 12d = 35

12d = 35 - 7

12d = 28

d = 28/12

d = 7/3

In an AP sum of the terms = n/2 ( a + an )

= 13/2 ( 7 + 35)

= 13/2 ( 42)

= 13(21)

= 273