For the following A.P.'s , write the first term and common difference :
(i) 2, 5, 8, 11, .... (ii) -5, -1, 3, 7, .....
(iii) 0.6, 1.7, 2.8, 3.9, ...... (iv) 5, 2, -1, -4, .....

Answer

To solve the problem, we need to identify the first term and the common difference for each given arithmetic progression (A.P.).

### Step-by-Step Solution:

**(i) For the A.P. 2, 5, 8, 11, ...**

1. **Identify the first term (A)**:
- The first term, denoted as \( A \), is the first number in the sequence.
- Here, \( A = 2 \).

2. **Calculate the common difference (d)**:
- The common difference is found by subtracting the first term from the second term.
- \( d = 5 - 2 = 3 \).

**Result for (i)**:
- First term: 2
- Common difference: 3

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**(ii) For the A.P. -5, -1, 3, 7, ...**

1. **Identify the first term (A)**:
- The first term is \( A = -5 \).

2. **Calculate the common difference (d)**:
- \( d = -1 - (-5) = -1 + 5 = 4 \).

**Result for (ii)**:
- First term: -5
- Common difference: 4

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**(iii) For the A.P. 0.6, 1.7, 2.8, 3.9, ...**

1. **Identify the first term (A)**:
- The first term is \( A = 0.6 \).

2. **Calculate the common difference (d)**:
- \( d = 1.7 - 0.6 = 1.1 \).

**Result for (iii)**:
- First term: 0.6
- Common difference: 1.1

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**(iv) For the A.P. 5, 2, -1, -4, ...**

1. **Identify the first term (A)**:
- The first term is \( A = 5 \).

2. **Calculate the common difference (d)**:
- \( d = 2 - 5 = -3 \).

**Result for (iv)**:
- First term: 5
- Common difference: -3

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### Final Summary:
- For (i): First term = 2, Common difference = 3
- For (ii): First term = -5, Common difference = 4
- For (iii): First term = 0.6, Common difference = 1.1
- For (iv): First term = 5, Common difference = -3