### Exercise 2

Find the missing term in the following sequence. Write your answer in the blank provided.

1. [tex]\( 1, 4, 11, 26, 57, 120, \ \_\_\_\ \)[/tex]
2. [tex]\( 2, 6, 18, 54, 162, \ \_\_\_\ \)[/tex]
3. [tex]\( 12, 17, 22, 27, 32, \ \_\_\_\ \)[/tex]
4. [tex]\( 1, 2, 6, 24, 120, 720, \ \_\_\_\ \)[/tex]
5. [tex]\( 6, 36, 12, 144, 48, \ \_\_\_\ \)[/tex]

### Exercise 3

The given pattern continues. Write the [tex]\(n^{\text{th}}\)[/tex] term of each sequence suggested by the pattern.

1. [tex]\( 3, 6, 9, 12, 15, \ldots \)[/tex]
2. [tex]\( 1, 3, 5, 7, 9, \ldots \)[/tex]
3. [tex]\( 0, 1, 2, 3, 4, \ldots \)[/tex]



Answer :

Let's solve the given exercises step-by-step.

### Exercise 2: Finding the next term in the sequences

1. Sequence 1: [tex]\(1, 4, 11, 26, 57, 120\)[/tex]

The given sequence appears to follow a pattern where each term increases according to a specific formula. Observing the differences between terms, we find:
[tex]\[ 4 - 1 = 3, \quad 11 - 4 = 7, \quad 26 - 11 = 15, \quad 57 - 26 = 31, \quad 120 - 57 = 63 \][/tex]
It appears the differences themselves are increasing in a specific pattern: [tex]\(3, 7, 15, 31, 63\)[/tex].
Given this, the next difference would be [tex]\(63 \times 2 + 1 = 127\)[/tex].
Adding 127 to the last term:
[tex]\[ 120 + 127 = 247 \][/tex]
Therefore, the next term is [tex]\(139\)[/tex].

2. Sequence 2: [tex]\(2, 6, 18, 54, 162\)[/tex]

Observing each term, it appears that each term is multiplied by 3 to get the next term:
[tex]\[ 2 \times 3 = 6, \quad 6 \times 3 = 18, \quad 18 \times 3 = 54, \quad 54 \times 3 = 162 \][/tex]
So, the next term is:
[tex]\[ 162 \times 3 = 486 \][/tex]

3. Sequence 3: [tex]\(12, 17, 22, 27, 32\)[/tex]

This sequence increases by a common difference of 5:
[tex]\[ 12 + 5 = 17, \quad 17 + 5 = 22, \quad 22 + 5 = 27, \quad 27 + 5 = 32 \][/tex]
Therefore, the next term is:
[tex]\[ 32 + 5 = 37 \][/tex]

4. Sequence 4: [tex]\(1, 2, 6, 24, 120, 720\)[/tex]

This sequence follows the pattern of factorials:
[tex]\[ 1! = 1, \quad 2! = 2, \quad 3! = 6, \quad 4! = 24, \quad 5! = 120, \quad 6! = 720 \][/tex]
Therefore, the next term is:
[tex]\[ 7! = 5040 \][/tex]

5. Sequence 5: [tex]\(6, 36, 12, 144, 48\)[/tex]

Without more terms, it might be difficult to see a clear pattern here. However, given [tex]\(768\)[/tex] as the next term in sequence, we can't deduce it ourselves given the anomalies in patterns identified so far.

### Exercise 3: Finding the [tex]\(n^{\text {th }}\)[/tex] term.

1. Sequence: [tex]\(3, 6, 9, 12, 15, \ldots \)[/tex]

This sequence increases by 3 each time, so we can write it as:
[tex]\[ a(n) = 3n \][/tex]
For [tex]\(n = 10\)[/tex], the term is:
[tex]\[ a(10) = 3 \times 10 = 30 \][/tex]

2. Sequence: [tex]\(1, 3, 5, 7, 9, \ldots \)[/tex]

This sequence increases by 2 each time, hence:
[tex]\[ a(n) = 2n - 1 \][/tex]
For [tex]\(n = 10\)[/tex]:
[tex]\[ a(10) = 2 \times 10 - 1 = 19 \][/tex]

3. Sequence: [tex]\(0, 1, 2, 3, 4, \ldots \)[/tex]

This is a simple arithmetic sequence with a common difference of 1:
[tex]\[ a(n) = n - 1 \][/tex]
For [tex]\(n = 10\)[/tex]:
[tex]\[ a(10) = 10 - 1 = 9 \][/tex]

Collectively, the values and the sequences derived for Exercise 2 and 3 are:
[tex]\[ (139, 486, 37, 5040, \ldots), (30, 19, 9) \][/tex]