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The sum of first four terms of an A.P. i...

The sum of first four terms of an A.P. is 56 and the sum of it's last four terms 112. If its first term is 11 then find the number of terms in the A.P

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11
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CBSE COMPLEMENTARY MATERIAL-SEQUENCES AND SERIES -SECTION-C(SHORT anwer type )
  1. Find the sum of the sequence, 72 + 70 + 68 + ………. + 40

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  2. If in an A.P (a(7))/(a(10))=(5)/(7),find (a(4))/(a(7))

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  3. The sum of first four terms of an A.P. is 56 and the sum of it's last ...

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  4. solve: 1 + 6 + 11 + 16 +.........+ x = 148

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  5. The ratio of the sum of n terms of two A.P.'s is (7n-1): (3n +11), fin...

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  6. If the first, second and the last terms of an A.P. are a,b,c respectiv...

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  7. If (b+c-2a)/(a), (c+a-2b)/(b),(a+b-2c)/(a) are in A.P then show that (...

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  8. The product of first three terms of a G.P. is 1000. If 6 added to its ...

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  9. If the continued product of three numbers in G.P. is 216 and the sum o...

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  10. Find the sum to infinity of the series: 1+3/2+5/2^2+7/2^3+..........oo

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  11. if A=1+r^a+r^(2a)+......... up to infinity then express r in terms of ...

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  12. Find the sum of first n terms of the series 0.7 + 0.77 + 0.777 + …..

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  13. "If "x=a+(a)/(r)+(a)/(r^(2))+...oo,y=b-(b)/(r)+(b)/(r^(2))-...oo,"and ...

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  14. The sum of first three terms of a G.P. is 15 and sum of next three ter...

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  15. Prove that 0.0031=7/225 [Hint: 0.031 = 0.03 + 0.001 + 0.0001 +.....Now...

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  16. If a ,\ b\ c are in G.P., prove that the following are also in G.P.: a...

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  17. If a ,\ b\ c are in G.P., prove that the following are also in G.P.: a...

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  18. If a, b, c are in G.P. that the following are also in G.P. sqrt(a),sqr...

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  19. If a, b, c are in A.P. that the following are also in A.P:(i)(1)/(bc),...

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  20. If a,b,c are in A.P. prove that b+c,c+a,a+b are also in A.P.

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