Question

if x=3+root8 find the value of x. square+1/xsquare

Answer 1

Heya

$x = 3 + \sqrt{8}$

$= > \frac{1}{x} = \frac{1}{(3 + \sqrt{8} )}$
$= \frac{ 3 - \sqrt{8} }{(3 + \sqrt{8)(3 - \sqrt{8} )} }$

$= \frac{3 - \sqrt{8} }{1}$

$= > (x + \frac{1}{x} ) = (3 + \sqrt{8} ) + (3 - \sqrt{8} ) = 6$

$= > (x + \frac{1}{x} )^{2} = 36$

$= > {x}^{2} + { \frac{1}{x} }^{2} = 34$