Question

if a = 3+ √8,then find the value of a-1/a​

Answer 1

Step-by-step explanation:

Given that a = 3+ √8....

Therefore,

$\frac{1}{a} = \frac{1}{3 + \sqrt{8} }$

By Rationalising the denominator,

$\frac{1}{3 + \sqrt{8} } \times \frac{3 - \sqrt{8} }{3 - \sqrt{8} } \\ \\ = > \frac{3 - \sqrt{8} }{9 - 8} = 3 - \sqrt{8}$

Therefore, substituting a and 1/a in the given equation, we get,

$a - \frac{1}{a} = (3 + \sqrt{8}) - (3 - \sqrt{8} ) \\ \\ = > 3 + \sqrt{8} - 3 + \sqrt{8} \\ \\ = > 2 \sqrt{8} = 4 \sqrt{2}$

Mark as Brainliest....

Answer 2

Answer:

hope it helps............