a. Un = 3n-1
b. Un =1/2n² - 2
c Un=2n/5
d. Un = n+n ² - 2
a. 2, 5, 8, 11, 14
b. -³⁄₂ 0, ⁵⁄₂, 6, ²¹⁄₂
c. ²⁄₅, ⁴⁄₅, ⁶⁄₅, ⁸⁄₅, ¹⁰⁄₅
d. 0, 4, 10, 18, 28
Penjelasan dengan langkah-langkah :
a. Uₙ = 3n - 1
U₁ = 3(1) - 1 = 3 - 1 = 2
U₂ = 3(2) - 1 = 6 - 1 = 5
U₃ = 3(3) - 1 = 9 - 1 = 8
U₄ = 3(4) - 1 = 12 - 1 = 11
U₅ = 3(5) - 1 = 15 - 1 = 14
∴ 5 suku pertama adalah 2, 5, 8, 11, 14
b. Uₙ = ¹⁄₂n² - 2
U₁ = ¹⁄₂(1)² - 2 = 1⁄2 - 2 = -³⁄₂
U₂ = ¹⁄₂(2)² - 2 = 2 - 2 = 0
U₃ = ¹⁄₂(3)² - 2 = ⁹⁄₂ - 2 = ⁵⁄₂
U₄ = ¹⁄₂(4)² - 2 = 8 - 2 = 6
U₅ = ¹⁄₂(5)² - 2 = ²⁵⁄₂ - 2 = ²¹⁄₂
∴ 5 suku pertama adalah -³⁄₂ 0, ⁵⁄₂, 6, ²¹⁄₂
c. Uₙ = ²ⁿ⁄₅
U₁ = ²⁽¹⁾⁄₅ = ²⁄₅
U₂ = ²⁽²⁾⁄₅ = ⁴⁄₅
U₃ = ²⁽³⁾⁄₅ = ⁶⁄₅
U₄ = ²⁽⁴⁾⁄5 = ⁸⁄₅
U₅ = ²⁽⁵⁾⁄₅ = ¹⁰⁄₅
∴ 5 suku pertama adalah ²⁄₅, ⁴⁄₅, ⁶⁄₅, ⁸⁄₅, ¹⁰⁄₅
d. Uₙ = n + n² - 2
U₁ = 1 + 1² - 2 = 2 - 2 = 0
U₂ = 2 + 2² - 2 = 6 - 2 = 4
U₃ = 3 + 3² - 2 = 12 - 2 = 10
U₄ = 4 + 4² - 2 = 20 - 2 = 18
U₅ = 5 + 5² - 2 = 30 - 2 = 28
∴ 5 suku pertama adalah 0, 4, 10, 18, 28
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