bonjour je suis en 3ème. pouvez-vous m'aider pour un exercice de maths-physique​

Bonjour,

1a) 1/R = 1/R1 + 1/R2

1/R = 1/2 + 1/5

1/R = (1 x 5)/(2 x 5) + (1 x 2)/(5 x 2)

1/R = 5/10 + 2/10

1/R = 7/10

R = 10/7 Ω

1b) 1/R = 1/4 + 1/13

1/R = 13/52 + 4/52

1/R = 17/52

R = 52/17 Ω

1c) 1/R = 1/11 + 1/13

1/R = 13/143 + 11/143

1/R = 24/142 Ω

2a) 1/R = 1/R1 + 1/R2

1/R - 1/R2 = 1/R1

1/R1 = 1/6 - 1/24

1/R1 = (1 x 4)/(6 x 4) - 1/24

1/R1 = 4/24 - 1/24

1/R1 = 3/24

R1 = 24/3 = 8 Ω

2b) 1/R1 = 1/1,1 - 1/1,7

1/R1 = 10/11 - 10/17

1/R1 = 170/187 - 110/187

1/R1 = 60/187 Ω