Question

已知：a=1/(2+根号)3,b=1/(2-根号3),求a^2-3ab+b^2的值

计算：2/(根号2-1)+根号18－4倍的根号1/2网友们快快快呀！

Answer 1

a=1/(2+根号)3=2-根号3
b=1/(2-根号3)=2+根号3
ab=1
a^2-3ab+b^2
=(a+b)²-5ab
=16-5
=11

Answer 2

a=1/(2+√3)=2-√3,b=1/(2-√3)=2+√3
a^2-3ab+b^2=(a-b)^2-ab=(2√3)^2-(2-√3)(2+√3)=12-1=11
2/(根号2-1)+根号18－4倍的根号1/2=2(√2+1)+3√2-2√2=3√2+2