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If x = 1 then Answer = 16 If x = 2 then Answer = 4 If x = 4 then Answer = 1 If x = 4/3 then Answer = 8 If x = 4/5 then Answer = 32
Thus we can have multiple answers for this question since value of x is not specified. Please correct the question or let me know if I have made a mistake.
If x = 1 then Answer = 16 If x = 2 then Answer = 4 If x = 4 then Answer = 1 If x = 4/3 then Answer = 8 If x = 4/5 then Answer = 32
Thus we can have multiple answers for this question since value of x is not specified. Please correct the question or let me know if I have made a mistake.
hi, you are absolutely correct in your observation.. looking at the equation and the OA, the equation could have been:- (2^a)^(a+b)/(2^b)^(a+b).. try out this Q ..
just a point, in these Q to save time, take the power to the numerator and then substitute for a and b.. example 2^a/2^b= 2^(a-b)= 2^(x + 1/x - x - (1/x)) = 2^(2/x)... you should do this when you see a and b have common terms with change of sign.. Ofcourse, the way you have done is also absolutely correct..
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Re: When a=x+(1/x) and b=x-(1/x), (2^a^2)/(2^b^2)=?
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04 Feb 2016, 22:09
I have an itching feeling that my method is grasping at too many straws, but it gave me the correct answer. Can anyone give me some feedback on my method for solving the question?
Re: When a=x+(1/x) and b=x-(1/x), (2^a^2)/(2^b^2)=?
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04 Feb 2016, 22:31
1
Hi @Beixi88,
Your solution focuses only on one of the solutions for 'a'. But a can also vary with the value of x.
According to your solution, we have one of the equations as x^2 - ax + 1 = 0. Here we have two unknowns x and a.. X and a can be plugged in many ways to solve the equation. If x = 2, 5 - 2a = 0 --> a = 5/2. Thus we can have many values of a depending on the value of x.
When a=x+(1/x) and b=x-(1/x), (2^a^2)/(2^b^2)=?
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Updated on: 08 Feb 2016, 21:30
When a=x+(1/x) and b=x-(1/x), (2^a)^2/(2^b)^2=?
A. 2 B. 4 C. 8 D. 16 E. 32
--> (2^a^2)/(2^b^2) ={(2)^(a^2-b^2)}=2^(a-b)(a+b). Since a-b=2/x and a+b=2x, 2^(a-b)(a+b)=2^(2/x)(2x)=2^4=16. Therefore, the answer is D.
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When a=x+(1/x) and b=x-(1/x), (2^a^2)/(2^b^2)=?
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08 Feb 2016, 20:55
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chetan2u wrote:
MathRevolution wrote:
When a=x+(1/x) and b=x-(1/x), (2^a)^2/(2^b)^2=?
A. 2 B. 4 C. 8 D. 16 E. 32
--> (2^a)^2/(2^b)^2 ={(2)^(a^2-b^2)}=2^(a-b)(a+b). Since a-b=2/x and a+b=2x, 2^(a-b)(a+b)=2^(2/x)(2x)=2^4=16. Therefore, the answer is D.
HI,
I am sorry, your solution is wrong,... (2^a)^2/(2^b)^2 = 2^(2a-2b) and not {(2)^(a^2-b^2)}
(2^a)^2=(2^a)*(2^a)=2^(a+a)= 2^2a.. REQUEST rectify the Question or the answer accordingly
Hi Bunuel, since you are the math expert here.. May I request you to inform MathRevolution to be slightly careful in the wordings of his Q. Inspite of observations raised by members, he just moves on to the next question without correcting the previous ones.
But this time he has gone beyond that. He has changed the power rule of exponent... (a^m)^n= a^mn..
I have nothing against the institute, but this attitude may harm the institute itself. that's ofcourse is their outlook but NOW we are teaching wrong things to students.. As, There will be many who will take his answer as correct since he is the source..
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Re: When a=x+(1/x) and b=x-(1/x), (2^a^2)/(2^b^2)=?
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29 Dec 2018, 12:14
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65% (01:52) correct 
