## Yahoo! 2 years ago 1+2+4+8+16+32.............. = ? Find the Sum

1. DhopeChickita

64, 128,256,512

2. Yahoo!

1 (1+2+4+8+16+32.............. ) (2-1)(1+2+4+8+16+32.............. ) = 2 + 4 +8+ 16 +32 ....... -1-2-4-8-16-32.......... = -1

3. DHASHNI

its infinity

4. Yahoo!

Lol...i knw....Nw tell me wats the wrong in my sloution

5. DHASHNI

huh they haven't given the last term and btw its basically a geometric progression

6. Yahoo!

Do u Find any mistake in the way i did....

7. DHASHNI

yeah !!!!! there is a mistake in ur where did that -1 come from????

8. Yahoo!

2-1 = 1...................lol

9. mayankdevnani

limit help....

10. mayankdevnani

... 4, 8, 16, 32 ... 512 or 4(1), 4(2), 4(4), 4(8), ... , 4(128) or 4(2^0), 4(2^1), 4(2^2), 4(2^3), ... , 4(2^7) S(n) = 4 ∑ 2^k [ k = 0 to n ] ....... = 4 [ 2^(n+1) - 1 ] S(7) = 4 [ 2^(7+1) - 1 ] ....... = 1020

11. Yahoo!

Lol....i dont need the answer..) i want to knw is there any mistake in my solution

12. mayankdevnani

don't angry @Yahoo! it's my limit

13. Yahoo!

lol....i am not angry ...this is a Funny....question....

14. mayankdevnani

just apply my method and get the answer

15. DHASHNI

@Yahoo! : its not that let the series be A by ur terms => (2-1)A =>2A -A =A

16. Yahoo!

oho...Again..... Tell me is there any wrong...lol

17. DHASHNI

got it!!!!

18. mayankdevnani

$\Huge{\bf{\color{blue}{i know you can }\color{red}{doit}}}$

19. furnessj

I hate these! I can't see see what is wrong but obviously there is something as it should total infinity... I would just do the 2-1 in the bracket and get the same answer... (is it not that there will always be one last term in the positive set of numbers which is much bigger than its negative counterpart in that set, and eventually that is infinity..?)

20. Yahoo!

1 (1+2+4+8+16+32.............. ) (2-1)(1+2+4+8+16+32.............. ) = 2 + 4 +8+ 16 +32 ....... -1-2-4-8-16-32.......... = -1

21. furnessj

Also... first terms, 2-1 = 1, second terms: 4-2 = 2, so you DO get the original series back, and it does NOT equal -1.

22. DHASHNI

2+4+8+16+32..................+2n 1+2+4+8+16+32............. + n {subtracting} ----------------------------- 1+2+4+8+16 +32+...........n

23. Yahoo!

take make sense @DHASHNI

24. DHASHNI

WAT!!!

25. Yahoo!

*that

26. Yahoo!

Sorry

27. furnessj

exactly @DHASHNI ! have a medal too :)

28. CliffSedge

You are subtracting sets of different cardinality. That's like adding unlike terms, you can't do it.

29. UnkleRhaukus

1 (1+2+4+8+16+32.............. ) (2-1)(1+2+4+8+16+32.............. ) = (2 + 4 +8+ 16 +32 +64+......)+( -1-2-4-8-16 -32 .........) = 63+.....