Wyznacz r ze wzoru. a) [latex]frac{E}{e} = frac{R+r}{r}[/latex] b) [latex]J = frac{zV}{R+2r}[/latex]

  [latex]frac{E}{e} = frac{R+r}{r}[/latex]   [latex]Er=e(R+r)[/latex]   [latex]Er=eR+er[/latex]   [latex]Er-er=eR[/latex]   [latex]r(E-e)=eR /:(E-e)[/latex]   [latex]r= frac{eR }{E-e}[/latex] =================== [latex]J = frac{zV}{R+2r}[/latex]   [latex]J(R+2r)=zV[/latex]   [latex]JR+2Jr=zV[/latex]   [latex]2Jr=zV-JR /:2J[/latex]   [latex]r= frac{zV-JR}{2J}[/latex]

a)   [latex]frac{E}{e}=frac{R+r}{r} /*r\\frac{Er}{e}=R+r /*e\\Er=(R+r)*e\Er=Re+re /-re\Er-re=Re\r(E-e)=Re /:(E-e)\r=frac{Re}{E-e}[/latex]   b)   [latex]J=frac{zV}{R+2r} /*(R+2r)\\J(R+2r)=zV\JR+2rJ=zV /-JR\2rJ=zV-JR /:2J\r=frac{zV-JR}{2J}[/latex]