a + \(\frac{1}{a}\) = 3 হলে, a2 + \(\frac{1}{{{a^{2\;}}}}\) = কত?
Solution
Correct Answer: Option A
দেওয়া আছে,
a + \(\frac{1}{a}\) = 3
প্রদত্ত রাশি = a2 + \(\frac{1}{{{a^{2\;}}}}\)
= (a)2 + (\(\frac{1}{a}\))2
= (a + \(\frac{1}{a}\))2 - 2 ⋅ a ⋅ \(\frac{1}{a}\) [∵ a2 + b2 = (a + b)2 - 2ab]
= (3)2 - 2
= 9 - 2
= 7
শর্টকাট টেকনিক:
যদি x + \(\frac{1}{x}\) = n হয়, তবে x2 + \(\frac{1}{x^{2}}\) = n2 - 2 হবে।
এখানে n = 3,
তাই নির্ণেয় মান = (3)2 - 2 = 9 - 2 = 7
a + \(\frac{1}{a}\) = 3
প্রদত্ত রাশি = a2 + \(\frac{1}{{{a^{2\;}}}}\)
= (a)2 + (\(\frac{1}{a}\))2
= (a + \(\frac{1}{a}\))2 - 2 ⋅ a ⋅ \(\frac{1}{a}\) [∵ a2 + b2 = (a + b)2 - 2ab]
= (3)2 - 2
= 9 - 2
= 7
শর্টকাট টেকনিক:
যদি x + \(\frac{1}{x}\) = n হয়, তবে x2 + \(\frac{1}{x^{2}}\) = n2 - 2 হবে।
এখানে n = 3,
তাই নির্ণেয় মান = (3)2 - 2 = 9 - 2 = 7
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