Question

化简(√a+√b)/(√a-√b) - (√a-√b)/(√a+√b)

Answer 1

(√a+√b)/(√a-√b) - (√a-√b)/(√a+√b)

=(√a+√b)(√a+√b)/[(√a-√b)(√a+√b) ]- (√a-√b)(√a-√b)/[(√a+√b)(√a-√b)]

=[(√a+√b)+(√a-√b)][(√a+√b)-(√a-√b) ]/[(√a-√b)(√a+√b) ]

=4√a√b/(a-b)