Question
1.
2.
3.
4.
Answer (Detailed Solution Below)
Option 3 : $27$
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Detailed Solution
सही उत्तर $27$ है।
Key Points
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prepsnap.in • Part -AQuestion:
If $x - \frac{1}{x} = 5$, then the value of $x^2 + \frac{1}{x^2}$ is: / यदि $x - \frac{1}{x} = 5$ हो, तो $x^2 + \frac{1}{x^2}$ का मान है:
1.
$23$
2.
$25$
3.
$27$
4.
$29$
Correct Answer: $27$
Correct — $(x - \frac{1}{x})^2 = x^2 + \frac{1}{x^2} - 2 = 25$, so $x^2 + \frac{1}{x^2} = 27$. Distractor (b) takes $5^2 = 25$ directly, forgetting the $-2$ cross-term sign flip. / सही उत्तर — $(x - \frac{1}{x})^2 = 25 = x^2 + \frac{1}{x^2} - 2$, अतः मान $27$। विकल्प (b) $-2$ पद भूलने की त्रुटि है।
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