Question

Stiind ca a²+1/a²=23,
calculați: ​

Answer 1

Răspuns:

${(a + \frac{1}{a} ) }^{2} = {a}^{2} + 2 + \frac{1}{ {a}^{2} } = 23 + 2 = 25$

deci

$({a + \frac{1}{a} })^{2} = \sqrt{25} = 5$

analog

$( {a - \frac{1}{a} })^{2} = \sqrt{21}$