Question

已知a等于根号下2加1,b等于根号下2减1,求b\a加a\b的值

Answer 1

因为a=√2+1,b=√2-1,
所以a+b=√2+1+√2-1=2√2,ab=(√2+1)(√2-1)=1,
所以a/b+b/a
=a²/ab+b²/ab
=(a²+b²)/ab
=[(a+b)²-2ab]/ab
=(2√2)²-2
=8-2
=6