(1)R=(R1*R2)/(R1+R2)(注:R不等于R2),求R1(2)已知(S/V)-S/(V+2)=1,求S
问题描述:
(1)R=(R1*R2)/(R1+R2)(注:R不等于R2),求R1
(2)已知(S/V)-S/(V+2)=1,求S
答
R=R*R2/(R-R2)
S=1/2V*(V+2)
答
①R=(R1R2)/(R1+R2)
R1R+R2R=R1R2
R2R=R1R2-R1R
R1=R2R/(r2-r)
②等式两边同时乘以 V(V+2) 得
(v+2)S-Sv=V(V+2)
S={V(V+2) }/2
答
原式=R(R1+R2)=R1R2 =RR1+RR2=R1R2 RR2=R1R2-RR1 RR2=R1(R2-R) RR2/(R2-R)=R12: S(V+2)/V(V+2)-SV/V(V+2)=1 [S(V+2)-SV]/V(V+2)=1 2S/V(V+2)=1 2S=V(V+2) S=V(V+2)/...