若x=根号2 减1,则x+x的负一次方=?
问题描述：
若x=根号2 减1,则x+x的负一次方=?
答
2倍根号2
答
x=√2-1
x+x^1
=x+1/x
=√2-1+1/(√2-1)
=√2-1+(√2+1)/(√2-1)(√2+1)
=√2-1+(√2+1)/(2-1)
=√2-1+√2+1
=2√2