If x4 + \(\frac{1}{x^4}\) = 27887, the positive value of ( x + \(\frac{1}{x}\) -3 ) is? |
13 12 11 10 |
10 |
If x4 + \(\frac{1}{x^4}\) = a then x2 + \(\frac{1}{x^2}\) = \(\sqrt {a + 2}\) = b and x + \(\frac{1}{x}\) = \(\sqrt {b + 2}\) ATQ, x4 + \(\frac{1}{x^4}\) = 27887 x2 + \(\frac{1}{x^2}\) = \(\sqrt {27887 + 2}\) = 167 So, ( x + \(\frac{1}{x}\) - 3 ) = ( \(\sqrt {167 + 2}\) - 3 ) = 10 |