1.

Find the value of \((2^{\frac14}-1)(2^{\frac34}+2^{\frac12}+2^{\frac14}+1)\)(a) 2 (b) 3 (c) 5 (d) 1

Answer»

(d) 1

\(\bigg(2^{\frac14}-1\bigg)\bigg(2^{\frac34}+2^{\frac12}+2^{\frac14}+1\bigg)\)

Let \(2^{\frac14}\) = a . Then, 

Given exp. = (a – 1) (a3 + a2 + a + 1 ) 

= (a – 1) (a2 (a + 1) + 1(a + 1)) 

= (a – 1) (a + 1) (a2 + 1) = (a2 – 1) (a2 + 1) 

= a4 – 1

∴ Required value = \(\big(2^{\frac14}\big)^4\) -1 = 2 - 1 = 1.



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