Learning task 2
B. After familiarizing yourself on finding the nth term of an arithmetic sequence, let us try to answer the exercises below. Find the term indicated in each of the following arithmetic sequences.
1.) 2, 4, 6, ... 15th term._____
2.) 13, 16, 19, 22, ... 25th term._____
3.) 99, 88, 77, 66, ... 18th term.______
4.) ¹/8, ¹/4, ³/8, ¹/2, ... 20th term._____
5.) 99, 87, 75, 63, ... 12th term._____
C. Solve what is asked:
1.) Insert four arithmetic means between -1 and 14.
2.) Insert five arithmetic means between 14 and 86.
3.) Insert three arithmetic means between -16 and 4.
Answers & Comments
Answer:
1. 30
2. 85
3. -88
4. 9/4 / -2.25
5. -33
Step-by-step explanation:
a1= 2
D= 2.
N= 15
an= a1 + (n-1) d.
a15 = 2 + ( 15-1 ) 2
2 + 14 (2)
2 + 28
= 30
a1= 13
D= 3
N= 25
a25 = 13 + ( 25-2 ) 3
13 + 24 (3)
13 + 72
=85
a1= 99
D= -11
N= 18
a18 = 99 + ( 18-1 ) -11
99 + 17 (-11)
99 + -187
= -88
a1= 1/8
D= -0.125
N= 20
a20 = 1/8 + ( 20-1 ) -0.125
1/8 + 19 (-0.125)
1/8 + -2.375
= -9/4 or -2.25
a1= 99
D= -12
N= 12
a12 = 99 + ( 12-1 ) -12
99 + 11 (-12)
99 + -132
= -33