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17 Jan 2024, 02:30
Kudos
Bookmarks
E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
82% (01:15) correct
18%
(01:11)
wrong
based on 97
sessions
History
Date
Time
Result
Not Attempted Yet
If \(a=x+\frac{1}{x}\) and \(b=x-\frac{1}{x}\), what is the value of \(a^2 – b^2\)?
A. \(x^2 + \frac{1}{x^2}\)
B. \(x^2 - \frac{1}{x^2}\)
C. \(1\)
D. \(2\)
E. \(4\)
A. \(x^2 + \frac{1}{x^2}\)
B. \(x^2 - \frac{1}{x^2}\)
C. \(1\)
D. \(2\)
E. \(4\)
17 Jan 2024, 08:33
Kudos
Bookmarks
Bunuel
\(a^2 = x^2+\frac{1}{x^2} +2*x*\frac{1}{x}=x^2+\frac{1}{x^2} +2\)
\(b^2 = x^2+\frac{1}{x^2} -2*x*\frac{1}{x}=x^2+\frac{1}{x^2} -2\)
Thus, \(a^2 - b^2 = (x^2+\frac{1}{x^2} +2) - (x^2+\frac{1}{x^2} -2)=4\), Answer must be (E)
17 Jan 2024, 22:07
Kudos
Bookmarks
Bunuel
OA is E
Attachments
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