R1:R2:R3=2:4:1,H1:H2:H3=2:1:4
1、R2^2:R1^2=4
2、R2H2:R3H3=4×1/4=1
3、R2^2H2:R1^2H1=4×1/2=2
4、R3^2H3:R1^2H1=(1/4)×2=1/2