Répondre :
A=2 et B=1+1/2+1/3+1/4+1/12
montrer que A=B
B=1+1/2+1/3+1/4+1/12
=12/12+6/12+4/12+3/12+1/12
=24/12
=2
=A
montrer que A=B
B=1+1/2+1/3+1/4+1/12
=12/12+6/12+4/12+3/12+1/12
=24/12
=2
=A