Home » Ask & Discuss » Mathematics. » Algebra « Back to Discussion

Algebra

Blazing goIITian

Joined:	13 Aug 2008
Post:	1313

28 Feb 2009 10:12:46 IST

0 People liked this

396

easy one i guess ....

None

Let S_n = . If T_n = S_n - 7 [ S_n/7 ], where [.] is gr8est int function,

what is T₁₀₀ ??

Share this article on:

Comments (4)

Yagyadutt Mishra

Forum Expert

Joined: 19 Feb 2009

Posts: 1984

28 Feb 2009 11:44:03 IST

Like 2 people liked this

[Sn/7] = Sn/7 - {Sn/7}.

7[Sn/7] = Sn - 7{Sn/7}.

Tn = Sn - Sn + 7{Sn/7}

Tn = 7{Sn/7}.

T100 = 7{S100/7}.

Now in S100 from |_7 upto |_100 all the value have 7 as the product so its fractional part will be zero.The fractional part will be only contribution of sum of term from |_1 to |_6....Its sum is equal to 873 which on dividing gives 124.7...so fractional part will be 0.7..and therefore, T100 = 7x0.7 = 4.9 ~ 5..

I think I am correct,,,if so plz rate,,And @ mirka It's not so easy..at the time of exam this question looks too much hard.

Mirka

Blazing goIITian

Joined: 13 Aug 2008

Posts: 1313

28 Feb 2009 12:37:08 IST

Like 0 people liked this

Answer given was 5 .....

Yagyadutt Mishra

Forum Expert

Joined: 19 Feb 2009

Posts: 1984

28 Feb 2009 12:43:04 IST

Like 0 people liked this

Sorry i got confused that 124.7 fractional point is 0.7 not 7.....so its 5,,i think you agree with my solution.

Mirka

Blazing goIITian

Joined: 13 Aug 2008

Posts: 1313

28 Feb 2009 12:57:34 IST

Like 0 people liked this

yes ... Thank u !

Quick Reply

Reply

	Some HTML allowed.
	Keep your comments above the belt or risk having them deleted.
	Signup for a avatar to have your pictures show up by your comment
	If Members see a thread that violates the Posting Rules, bring it to the attention of the Moderator Team