a.67,62,57,52,...,...,...
b.2,4,8,16,32,...,...
2.tentukan 5 suku pertama dari barisan dengan rumus ke-n sebagai berikut!
a.Un=2n²-1
b.Un=3n(n-1)
3.tentukan rumus pola bilangan ke-n pada barisan bilangan berikut!
a.10,11,12,13,14,....
b.25,13,11,9,7,....
Jawab:
1. a. 67, 62, 57, 52, 47, 42, 37
b. 2, 4, 8, 16, 32, 64, 128, 256
2. a. 1, 7, 17, 31, 49
b. 3, 6, 18, 36, 60
3. a. 15
b. 5
Penjelasan dengan langkah-langkah:
1. a. 67-62=5
52-5=47, dst. jadi tiap bilangan selisih 5 angka
b. kelipatan 2, jadi 2x2=4, 4x2=8, .... 32x2=64
2. a. 2.1²-1 = 2.(1x1)-1 = 1
2.2²-1 = 2.(2x2)-1 = 2.4-1 = 8-1 = 7
2.3²-1 = 2.(3x3)-1 = 2.9-1 = 18-1 = 17
2.4²-1 = 2.(4x4)-1 = 2.16-1= 32-1 = 31
2.5²-1 = 2.(5x5)-1 = 2.25-1 = 50-1 = 49
b. 3.1(1-1) = 3.1 = 0
3.2(2-1) = 6.1 = 6
3.3(3-1) = 9.2 = 18
3.4(4-1) = 12.3 = 36
3.5(5-1) = 15.4 = 60
Note: tanda . itu artinya kali
3. a. Pola penjumlahan 1 angka
b. Pola pengurangan 2 angka
Semoga membantu
Jawab:
Penjelasan dengan langkah-langkah:
1.
[tex]a)\; U = \{67,62,57,52,...\}\to a = 67, b = 62-67 = -5\\U_n = 67 - 5(n-1) = 72 - 5n\\\boxed{\boxed{ U_5 = 72-25 = 47 ,U_6 = 47-5 = 42 ,U_7 = 42-5 = 37 }}[/tex]
[tex]b)\; U = \{2,4,8,16,...\}\to a = 2, b = 4-2 = 2\\U_n = 2 + 2(n-1) = 2n\\\boxed{\boxed{ U_5 = 2\times 5 = 10 ,U_6 = 10+2 = 12 ,U_7 = 12+2 = 14 }}[/tex]
2.
[tex]a)\; U = \{2\cdot 1^2-1,2\cdot 2^2-1,2\cdot 3^2-1,2\cdot 4^2-1,2\cdot 5^2-1\}\\\boxed{\boxed{U = \{1,7,17,31,49\}}}[/tex]
[tex]b)\;U = \{3\cdot 1 (1-1),3\cdot 2 (2-1),3\cdot 3 (3-1),3\cdot 4 (4-1),3\cdot 5 (5-1)\}\\\boxed{\boxed{U=\{0,6,18,36,60\}}}[/tex]
3.
[tex]a)\; U = \{10,11,12,13,14\}\to a = 10, b = 1\to \boxed{\boxed{U_n = n+9}}[/tex]
[tex]b)\; U = \{15,13,11,9,7\}\to a = 15, b = 13-15 = -2\to \boxed{\boxed{U_n = 17-2n}}[/tex]
[answer.2.content]
