Bonjour pouvez vous m'aider s'il vous plaît merci

ex 20 :
a) u(0)=5, u(1)=9, u(2)=13, u(3)=17, u(4)=21, u(10)=45
b) u(0)=0, u(1)=1, u(2)=4, u(3)=9, u(4)=16, u(10)=100
c) u(0)=1, u(1)=-2, u(2)=4, u(3)=-8, u(4)=16, u(10)=1024
d) u(0)=-1/2, u(1)=0, u(2)=1/4, u(3)=2/5, u(4)=1/2, u(10)=3/4

Bonjour,

Exercice 20 :

calculer U0, U1, U2, U3, U4, U10 :

a) Un = 4n + 5
U0 = 4 x 0 + 5 = 5
U1 = 9
U2 = 13
U3 = 17
U4 = 21
U10 = 45

b) Un = n²
U0 = 0² = 0
U1 = 1
U2 = 4
U3 = 9
U4 = 16
U10 = 100

c) Un = (-2)^n
U0 = (-2)^0 = 1
U1 = (-2)
U2 = 4
U3 = (-8)
U4 = 16
U10 = 1024

d) Un = (n - 1)/(n + 2)
U0 = (0 - 1)/(0 + 2) = (-1/2)
U1 = 0
U2 = 1/4
U3 = 2/5
U4 = 3/6 = 1/2
U10 = 9/12 = 3/4

Exercice 21 :

calculer U0, U1, U2, U3, U4, U100 :

a) Un = 4^n - 3n
U0 = 4^0 - 3 x 0 = 1
U1 = 1
U2 = 10
U3 = 55
U4 = 244
U100 = 1,6 x 10^60

b) Un = 1,05^n
U0 = 1,05^0 = 1
U1 = 1,05
U2 = 1,1025
U3 ≈ 1,16
U4 ≈ 1,22
U100 ≈ 131,5

c) Un = sin(nπ/2)
U0 = sin(0) = 0
U1 = Sin(π/2)
U2 = Sin(π)
U3 = Sin(3π/2)
U4 = Sin(2π)
U100 = Sin(50π)

d) Un = 2 + (-1)^n
U0 = 2 + (-1)^0 = 2
U1 = 1
U2 = 3
U3 = 1
U4 = 3
U100 = 3