Question

1.Di ketahui barisan bilangan 3,6,12,24,....... tentukan:
A.rumus suku ke-n;
B.nilai suku ke-8.
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2.Diketahui barisan bilangan 5,8,13,20,........tentukan:
A.rumus suku ke-n;
B.nilai suku ke-22.

Tolong di jawab ya kak

Answer 1

1. 4a = 4

a = 1

4a + b = 3

4 (1) + b = 3

4 + b = 3

b = 1

a + b + c = 3

1 + 1 + c = 3

2 + c = 3

c = 1

Un = an² + bn + c

Un = 1.n² + 1.n + 1

Un = n² + n

U8 = 8²

U8 = 64

2. 5a = 5

a = 1

5a + b = 2

5 (1) + b = 2

5 + b = 2

b = 3

a + b + c = 5

1 + 3 + c = 5

4 + c = 5

c = 1

Un = an² + bn - c

Un = 1.n² + 3.n - 1

Un = n² + 3n - 1

U22 = 22² + 3 (22) - 1

U22 = 484 + 66 - 1

U22 = 484 + 65

U22 = 549