1
Akand
·2009-03-12 08:56:12
can we convert into 1728.............and do sumthing about it???
1
Anuj
·2009-03-12 13:41:22
why dont try taking log?????it will simplify things a lot.........
39
Dr.House
·2009-03-12 11:51:45
caculations may become cumbersome but congruencies can help.
1
Philip Calvert
·2009-03-12 11:41:26
17 ^ 2 leaves 289
17 ^ 4 leaves 521
17 ^ 8 --- 441
17 ^ 16 -- - 481
17 ^ 32 ---- 361
17 ^ 64 -- 321
17 ^ 128 ------ 41
17 ^ 256 ---- 681
im sorry but it was really long and boring two digits would have been much better.........but three is a waste.......
anyway thats the answer......
1
Philip Calvert
·2009-03-12 11:36:01
this is not that tuff or long.....( it is long)
especially since the power is 256........
1
Akand
·2009-03-12 09:08:19
(300)power......will always end with zeroes.....
so
128C0-128C1(11)..............-128C127(11)127(300)+(11)128
1
kamalendu ghosh
·2009-03-12 09:08:02
Yes it is.... calculations a bit easies thanxxx
1
Akand
·2009-03-12 09:06:34
i think easier way will be taking it as ....(300-11)to d power128....
128C0(300)128-128C1(300)127(11)........+128c128(11)128
1
kamalendu ghosh
·2009-03-12 09:04:56
I hope u got it?
Sorry if i have wasted ur time if u think it a nit-so-worthy at this point of time sum
1
Akand
·2009-03-12 09:03:23
dude.....sorry to point this out............but a small mistake in ur expansion...........ur second last term must be negative and third last positive..............
1
kamalendu ghosh
·2009-03-12 08:59:50
17 to the powr 256 = (172) to the power 128
= (290 - 1)to the power 128
= .... .... ... ... ..- 128C125(2903) + 128C126(2902) - 128C127(290) + 1(290) + 1
= 1000k - 128C126(2902) - 128C127(290) + 1(290) + 1
Now calcul;ate bit to get 681 as the answer
1
Akand
·2009-03-12 08:36:31
wel last digit is 1.............must think bout d oder 2
1
KR
·2009-03-12 08:52:38
i think we will get if we use modulo
1
Akand
·2009-03-12 08:51:40
ya as sky said......findin last digit is enuf i guess...(at this stage).... but i do want a solution for this......
1
kamalendu ghosh
·2009-03-12 08:50:42
Well sky, I can find the last 5 digitd but it wud need a bit big multiplications.....
well, were u avle to solve it or not?
1
kamalendu ghosh
·2009-03-12 08:49:01
U cant follow that method for finding the last 3 digits... that can be done only for the last digit
1
skygirl
·2009-03-12 08:47:58
dun bash me this way guys.... am sry to say it in dat way if it did hurt u all...
but if i ask u abt the 5th last digit... how will u find it ...
well nishant bhiaya told its a 'wat to say' ... not worth-doing question r8 now...
sry once agn...
1
Akand
·2009-03-12 08:44:25
guys ............for d first few multiples i got d second digits as......(i used a calculator though)..1 8 1 2 5 6 7 4.........no specific trend.....
1
Akand
·2009-03-12 08:41:32
no question is stupid sky................ and also u dint get d answer for it ok??
1
kamalendu ghosh
·2009-03-12 08:40:38
Really??? Well It came in RESONANCE AITS last Sunday..... But it isnt a bad question ??? Y do u feel that?/
1
skygirl
·2009-03-12 08:39:18
http://targetiit.com/iit_jee_forum/posts/last_digit_3209.html
chcek here.
1
skygirl
·2009-03-12 08:37:21
hey this is a bad question.... i asked this few days ago....