Search found 20 matches
Sushanta, If I understood you right u r saying sqrt(16) can be +4 or -4 correct. sqrt(x) is always equal to |x| i.e absolute value of x. This is called the principal square root of x that applies to math world and GMAT. Prinicipal square root of a number is the unique nonnegative square root of a n...
- by sushanta57021
Fri Nov 14, 2008 7:53 pm- Forum: Data Sufficiency
- Topic: algebra
- Replies: 11
- Views: 2223
Re: algebra
Alright, root of a negative number is called imaginary number. http://en.wikipedia.org/wiki/Imaginary_number You can also call it NOT REAL. Thanks for your info. But i think i know the definition of imaginary no. What i wanted to mean was, this info is irreverent to the problem. the question starte...
- by sushanta57021
Fri Nov 14, 2008 6:54 pm- Forum: Data Sufficiency
- Topic: algebra
- Replies: 11
- Views: 2223
Re: algebra
16^(1/2) = +4 or - 4 YOU ARE RIGHT BUT, (-16)^(1/2) = Is not a real number. SO INSIDE OF THE ROOT needs to be POSITIVE (+) , not OUTSIDE OF IT! Clear now ? -4 = {-(-4)x4}^1/2 is there any with the above eqn. that means if X= -4, then also the above equation can be -4, that is X. i am trying to expl...
- by sushanta57021
Fri Nov 14, 2008 5:03 pm- Forum: Data Sufficiency
- Topic: algebra
- Replies: 11
- Views: 2223
Re: Another Question
A box contains 10 light bulbs, fewer than half of which are defective. Two bulbs are to be drawn simultaneously from the box. If n of the bulbs in box are defective, what is the value of n? (1) The probability that the two bulbs to be drawn will be defective is 1/15. (2) The probability that one of...
- by sushanta57021
Fri Nov 14, 2008 3:05 pm- Forum: Data Sufficiency
- Topic: Another Question
- Replies: 7
- Views: 1819
Re: algebra
[/quote] How about we make life simple and just pick x=-4 and sub in. (Note that i'm picking a negative number because otherwise we'll end up taking the root of a negative, which doesn't work out so well!) [-X{abs(X)}]^1/2 [4(4)]^1/2 (16)^1/2 4 When we plug in -4 to the choices, only (a) gives us &q...
- by sushanta57021
Fri Nov 14, 2008 2:28 pm- Forum: Data Sufficiency
- Topic: algebra
- Replies: 11
- Views: 2223
we are given p = sqrt(-x|x|) where x<0 lets go by ur approach that soln is +x, it shall satisfy the equation. p = sqrt(-x.x) since we took the solution as +x p = sqrt(-x^2) now, tell me how will you solve this as p = +x? Hope you get the point now. That if we put the values and backsolve, only -x w...
- by sushanta57021
Fri Nov 14, 2008 11:35 am- Forum: Problem Solving
- Topic: algebra
- Replies: 14
- Views: 2013
Re: potato cyst
Potato cyst nematodes are a pest of potato crops. The nematodes can lie dormant for several years in their cysts, which are protective capsules, and do not emerge except in the presence of chemicals emitted by potato roots. A company that has identified the relevant chemicals is planning to market ...
- by sushanta57021
Fri Nov 14, 2008 9:40 am- Forum: Critical Reasoning
- Topic: potato cyst
- Replies: 15
- Views: 3122
Re:algebra
sorry for posting it twice, but first i posted it in the wrong forum, i.e DS forum. But anyway, I am not convinced with the answer yet. We cann't take -X as answer only because X<0. let me explain: Say, P = [-X{abs(X)}]^1/2 is there any reason why P has to be positive? P can be negetive also, that ...
- by sushanta57021
Fri Nov 14, 2008 9:26 am- Forum: Problem Solving
- Topic: algebra
- Replies: 14
- Views: 2013
- by sushanta57021
Thu Nov 13, 2008 10:59 pm- Forum: Critical Reasoning
- Topic: Choice of software
- Replies: 8
- Views: 1959
Re: potato cyst
Potato cyst nematodes are a pest of potato crops. The nematodes can lie dormant for several years in their cysts, which are protective capsules, and do not emerge except in the presence of chemicals emitted by potato roots. A company that has identified the relevant chemicals is planning to market ...
- by sushanta57021
Thu Nov 13, 2008 10:21 pm- Forum: Critical Reasoning
- Topic: potato cyst
- Replies: 15
- Views: 3122
Re:algebra
sorry for posting it twice, but first i posted it in the wrong forum, i.e DS forum. But anyway, I am not convinced with the answer yet. We cann't take -X as answer only because X<0. let me explain: Say, P = [-X{abs(X)}]^1/2 is there any reason why P has to be positive? P can be negetive also, that ...
- by sushanta57021
Thu Nov 13, 2008 7:06 pm- Forum: Problem Solving
- Topic: algebra
- Replies: 14
- Views: 2013
- by sushanta57021
Thu Nov 13, 2008 12:14 pm- Forum: Data Sufficiency
- Topic: GMATPrep Integers
- Replies: 9
- Views: 3638
well, atleast can some one please tell me whether my logic is right.
I am expecting some answer from you guys.
Thnaks,
Sushanta.
- by sushanta57021
Thu Nov 13, 2008 11:42 am- Forum: Problem Solving
- Topic: algebra
- Replies: 14
- Views: 2013
Re:algebra
sorry for posting it twice, but first i posted it in the wrong forum, i.e DS forum. But anyway, I am not convinced with the answer yet. We cann't take -X as answer only because X<0. let me explain: Say, P = [-X{abs(X)}]^1/2 is there any reason why P has to be positive? P can be negetive also, that m...
- by sushanta57021
Thu Nov 13, 2008 11:25 am- Forum: Problem Solving
- Topic: algebra
- Replies: 14
- Views: 2013
Re:algebra
Let X = -2
[-(-2){-2}]^1/2
2*2^1/2
4^1/2
2
Note: {}=Absolute value
So x = -x
But 4^1/2 can be +2 or -2.
hence answer can be +X or -X.
please explain.......
- by sushanta57021
Thu Nov 13, 2008 11:06 am- Forum: Problem Solving
- Topic: algebra
- Replies: 14
- Views: 2013