Réponse :

Explications étape par étape

Bonjour

A = 1 / (1 + 1 / (1 + 1/3))

A = 1 / (1 + 1 / (3/3 + 1/3))

A = 1 / (1 + 1 / (4/3))

A = 1 / (1 + 1 x 3/4)

A = 1 / (1 + 3/4)

A = 1 / (4/4 + 3/4)

A = 1 / (7/4)

A = 1 x 4/7

A = 4/7

B = 2 / (2 - 1 / (2 - 1 / (2 - 1/2)))

B = 2 / (2 - 1 / (2 - 1 / (4/2 - 1/2)))

B = 2 / (2 - 1 / (2 - 1 / (3/2)))

B = 2 / (2 - 1 / (2 - 1 x 2/3))

B = 2 / (2 - 1 / (2 - 2/3))

B = 2 / (2 - 1 / (6/3 - 2/3))

B = 2 / (2 - 1 / (4/3))

B = 2 / (2 - 1 x 3/4)

B = 2 / (2 - 3/4)

B = 2 / (8/4 - 3/4)

B = 2 / (5/4)

B = 2 x 4/5

B = 8/5