Question

(a + 1/a) ^ 2 - (a - 1/a) ^ 2​

Answer 1

$(a + \frac{1}{a} ) ^{2} - (a - \frac{1}{a} ) ^{2}$

$= \frac{4a ^{2} }{ {a}^{2} }$

$= 4 \: ( \: cancel \: {a}^{2} )$