Răspunsuri

2014-02-11T22:22:21+02:00
R=p(ro)x l / S
S=pi x r2(r la patrat, r e raza)=pi x d2(d patrat) / 4
=>R=p(ro) x 4 l / pi x d2
i=E/(R+r)=>iR+ir=E=>r=(E-iR)/i=>r=E/i - R=>r=E/i - (4 x p x l) / (pi x d2)