a=2+√3,b=2-√3
所以ab=(2+√3)(2-√3)=4-3=1
√ab=1
a+b=(2+√3)+(2-√3)=4
（a+√ab\√ab+b）+（√ab-b\a-√ab）
=(a+1)/(1+b)+(1-b)/(a-1)
=(a²-1+1-b²)/[(1+b)(a-1)] 通分
=(a²-b²)/(a+ab-b-1)
=(a+b)(a-b)/(a+1-b-1)
=(a+b)(a-b)/(a-b)
=a+b
=4需要先化簡(jiǎn)的。（a+√ab\√ab+b）+（√ab-b\a-√ab）=(a²-ab+ab-b²)/[(√ab+b)(a-√ab)]=(a+b)(a-b)/(a√ab+ab-ab-b√ab)=(a+b)(a-b)/(a√ab-b√ab)=(a+b)(a-b)/[(a-b)√ab]=(a+b)/√ab=(a+b)√ab/ab=4