(3.6* 10^6)/(2*10^10)
=(3.6/2)*(10^6//10*10)=1.8*10^-4
即1.8乘以10的-4次方
(根号3-2)/(-1/2)
=(2-根号3)/(1/2)
=2*(2-根号3)
=4-2根号3