Answer:
The correct option is B) 5, 5, 5, 5, 5 and C) 3, 6, 9, 12, 15 are arithmetic sequences
Step-by-step explanation:
Arithmetic sequence is: a, a+r, a+2r, a+3r, a+4r, ....... where r is common difference
Check part A) 1, 1, 2, 5, 8, 13
In which [tex]a_1=1,\, a_2=1,\,a_3=2,\,a_4=5[/tex]
common difference [tex]d=a_n+1 -a_n[/tex]
[tex]d=a_2 -a_1 =1-1=0 [/tex]
[tex]d=a_3 -a_2 =2-1=1 [/tex]
since common difference is not same
so, sequence 1, 1, 2, 5, 8, 13 is not arithmetic sequences.
Check part B) 5, 5, 5, 5, 5
In which [tex]a_1=5,\, a_2=5,\,a_3=5,\,a_4=5[/tex]
common difference [tex]d=a_n+1 -a_n[/tex]
[tex]d=a_2 -a_1 =5-5=0 [/tex]
[tex]d=a_3 -a_2 =5-5=0 [/tex]
since common difference is same
so, sequence 5, 5, 5, 5, 5 is arithmetic sequences.
Check part C) 3, 6, 9, 12, 15
In which [tex]a_1=3,\, a_2=6,\,a_3=9,\,a_4=12[/tex]
common difference [tex]d=a_n+1 -a_n[/tex]
[tex]d=a_2 -a_1 =6-3=3 [/tex]
[tex]d=a_3 -a_2 =9-6=3 [/tex]
since common difference is same
so, sequence 3, 6, 9, 12, 15 is arithmetic sequences.
Check part D) 2, 4, 8, 16, 32
In which [tex]a_1=2,\, a_2=4,\,a_3=8,\,a_4=16[/tex]
common difference [tex]d=a_n+1 -a_n[/tex]
[tex]d=a_2 -a_1 =4-2=2 [/tex]
[tex]d=a_3 -a_2 =8-4=4 [/tex]
since common difference is not same
so, sequence 2, 4, 8, 16, 32 is not arithmetic sequences.
Therefore, the correct option is B) 5, 5, 5, 5, 5 and C) 3, 6, 9, 12, 15 are arithmetic sequences
