১.
If a + (1/a) = √3 then what is the value of {a3 + (1/a3) + a + (1/a)}2?
সঠিক উত্তর: গ
3
উত্তর
সঠিক উত্তর: গ
3
ব্যাখ্যা
Question: If a + (1/a) = √3 then what is the value of {a3 + (1/a3) + a + (1/a)}2?
Solution:
Now,
a3 + (1/a3) + a + (1/a)
= a3 + (1/a3) + a + (1/a)
= {a + (1/a)}3 - 3 · a · (1/a){a + (1/a)} + {a + (1/a)}
= (√3)3 - 3√3 + √3
= 3√3 - 3√3 + √3
= √3
∴ {a3 + (1/a3) + a + (1/a)}2 = (√3)2 = 3
Solution:
Now,
a3 + (1/a3) + a + (1/a)
= a3 + (1/a3) + a + (1/a)
= {a + (1/a)}3 - 3 · a · (1/a){a + (1/a)} + {a + (1/a)}
= (√3)3 - 3√3 + √3
= 3√3 - 3√3 + √3
= √3
∴ {a3 + (1/a3) + a + (1/a)}2 = (√3)2 = 3