Réponses

2013-05-30T12:35:26+02:00

Bonjour,

 

Ex2)

1a)

Un+1 = Un+r

Un+1 = Un-250

1b)

U1 = 5000-250 = 4750

U2 = 4750-250 = 4500

U3 = 4500-250 = 4250

2a)

Un = Uo+nr

Un = 5000-250n

2b)

U20 = 5000-20*250 

U20 = 5000-5000

U20 = 0

3)

Si Un = 1/2 Uo  Un = 5000/2 = 2500

Un = 5000-250n = 2500

250n = 5000-2500 = 2500

n = 2500/250

n = 10

 

Ex3)

1a)

Cn+1 = q*Cn  --> q = 1.0225

1b)

Co = 1000

C1 = 1022.5

C2 = 1045.50625

C3 = 1069.030140625

 

2)

 

C_n=C_o*q^n

 

3)

C31 = 1993.25479293274

C32 = 2038.10302577373

 

Si C_n\geq2C_0

 

C_n\geq2000

 

C_3_1<2000

 

C_3_2>2000

 

--> n = 32

 

J'espère que tu as compris

a+