Question

Tentukan 4 suku pertama dari barisan bilangan :
1. Un = -2n + 7
2. Un = 1/5 n³-3n+4

wajib di jwb semuanyaaaa

Answer 1

1. U1 = -2(1) + 7 = -2 + 7 = 5
    U2 = -2(2) + 7 = -4 + 7 = 3
    U3 = -2(3) + 7 = -6 + 7 = 1
    U4 = -2(4) + 7 = -8 + 7 = -1

2. U1 = 1/5 x 1³ - 3(1) + 4 = 1/5 x 2 = 2/5
    U2 =1/5 x 2³ - 3(2) + 4 = 8/5 x 6 = 48/5
    U3 = 1/5 X 3³ - 3(3) + 4 = 22/5
    u4 = 1/5 X 4³ - 3(4) + 4 = 56/5

Answer 2

1.
un= -2n + 7
u1 = -2x1 +7 = -2 + 7 = 5
u2=-2x2 +7 = -4 +7 = 3
u3= -6+7 = 1
u4= -8+7 =-1
u5= -10+7= -3

5 , 3 ,1 ,-1

2. 
un= 1/5n^3 - 3n + 4
u1= 1/5x1 - 3.1 +4 =1/5 +1 = 5/5 + 1/5= 6/5

u2= 1/5x8 - 6+4 = 8/5 - 2 = 8/5 - 10/5 = - 2/5

u3= 1/5 x 27 - 9 +4 = 27/5 -5  = 27/5 - 25/5 =2/5

u4= 1/5 x 64 - 12 +4 = 64/5 - 8 = 64/5-40/5= 24/5

6/5 , -2/5 , 2/5, 24/5