$(1-b/(a+b))(1+b/(a-b))(1-b^2 / a^2)$

A cura di: Antonio Bernardo

$(1-b/(a+b))(1+b/(a-b))(1-b^2 / a^2)$

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$(a+b-b)/(a+b) * (a-b+b)/(a-b) * (a^2 -b^2)/a^2$

$a/(a+b) * a/(a-b) * ((a-b)(a+b))/a^2=1$

semplificando numeratori con denominatori