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If {an} is a G.P. and a1=4,r=5, find a6 ...

If `{a_n}` is a G.P. and `a_1=4`,r=5, find `a_6` and `S_6`.

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MODERN PUBLICATION-SEQUENCES AND SERIES-EXERCISE
  1. Given a G.P. with a= 1,r= sqrt2. Find S20.

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  2. Given a G.P. with a= 729 and 7th term 64, determine S7.

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  3. If {an} is a G.P. and a1=4,r=5, find a6 and S6.

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  4. Find a G.P. for which sum of the first two terms is -4 and the fifth t...

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  5. The sum of first three terms of a G.P. is 16 and the sum of the next t...

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  6. The sum of some terms of GP. is 315 whose first term and the common ra...

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  7. Find the sum to.n terms of the following series 5+ 55 + 555+………..

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  8. Sum to n terms: 9+ 99 + 999 + ......

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  9. Sum to n terms: 3 + 33+ 333 +..........

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  10. Find the sum of the sequence 7, 77, 777, 7777,.....up to n terms.

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  11. Sum to n terms: 8 + 88 + 888+..........

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  12. The sum of first 20 terms of the sequence 0.7,0.77,0.777,"……" is

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  13. Find the sum to n terms 0.6 + 0.66 + 0.666 + ………..

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  14. Sum to n terms: 0.3+ 0.33 +0.333 +.......

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  15. Sum to n terms: 0.5+0.55 + 0.555 +...

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  16. Find the sum to n terms 0.6 + 0.66 + 0.666 + ………..

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  17. If 1/(1+l)=v, prove that : v+v^(2)+v^(3)+………+v^(n)=(1-v^(n))/l.

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  18. Find the sum to n terms of the sequence : 1,-1,1,-1,........ ,(-1)^(n+...

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  19. If the sum of first 10 terms is 33 times the sum of first 5 terms of G...

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  20. Show that the ratio of the sum of first n terms of a G.P. to the sum o...

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