若a=2+√3,b=2-√3,求(a-√ab）分之（a)-(√a+√b）分之√b的值

若a=2+√3,b=2-√3,求(a-√ab）分之（a)-(√a+√b）分之√b的值
若a=2+√3,b=2-√3,求(a-√ab）分之（a)-(√a+√b）分之√b的值

若a=2+√3,b=2-√3,求(a-√ab）分之（a)-(√a+√b）分之√b的值
a/(a-√ab)-√b/(√a+√b)
=a/[√a(√a-√b)]-√b/(√a+√b)
=√a/(√a-√b)-√b/(√a+√b)
=[√a(√a+√b)-√b(√a-√b)]/(a-b)
=(a+b)/(a-b)
=4/(2√3)
=(2√3)/3

[a/(a-√ab)]-[√b/(√a+√b)]
=[√a/(√a-√b)]-[√b/(√a+√b)]
=[√a(√a+√b)-√b/(√a-√b)]/(a-b)
=(a+b)/(a-b)
把a,b代入有
该式等于(2√3)/3