八下二次根式：已知a=1/根号2+1,b=1/根号3+根号2,求(a+b)^2的值.

a=1/(√2+1)
=1*(√2-1)/[(√2+1)(√2-1)]
=√2-1
b=1/(√3+√2)
=1*(√3-√2)/[(√3+√2)(√3-√2)]
=√3-√2
(a+b)^2
=(√2-1+√3-√2)^2
=(√3-1)^2
=3-2√3+1
=4-2√3