Question

Решите номер 42.Есть вложение.

Answer 1

$x+ frac{1}{x} =2.5 \ (x+ frac{1}{x} )^2=2.5^2 \ x^2+2+ frac{1}{x^2} =6.25 \ x^2+ frac{1}{x^2} =6.25-2 \ x^2+ frac{1}{x^2} =4.25$

$frac{1}{a} -a=1.2 \ ( frac{1}{a} -a)^2=1.2^2 \ frac{1}{a^2} -2+a^2=1.44 \ frac{1}{a^2} +a^2=1.44+2 \ frac{1}{a^2} +a^2=3.44$