Répondre :
a)
R=(R1*R2)/(R1+R2)
=(4*6)/(4+6)
=2,4 ohms
b)
5=(12R2)/(R2+12)
5R2+60=12R2
7R2=60
R2=8,57 ohms
R=(R1*R2)/(R1+R2)
=(4*6)/(4+6)
=2,4 ohms
b)
5=(12R2)/(R2+12)
5R2+60=12R2
7R2=60
R2=8,57 ohms