Question

2010.10.如果a=4+√3,b=13 / 4+√3 求a/a-ab -√b/√a+√b./=分号.如:xx分之xx

Answer 1

=13(4-√3)/(16-3)=4-√3

原式=(√a)²/√a(√a-√b)-√b/(√a+√b)

=√a/(√a-√b)-√b/(√a+√b)

通分

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

=(a+√ab-√ab+b)/(a-b)

=(a+b)/(a-b)

=(4+√3+4-√3)/(4+√3-4+√3)

=8/(2√3)

=4√3/3