In an arithmetic sequence, the common difference (d) is the constant difference between any two consecutive terms. To find the common difference, u can use the formula:
an = a1 + (n-1)d
where an is the nth term of the sequence, a1 is the first term, and d is the common difference.
U are given that a2 = 1 and a5 = 7. Using the above formula, u can write:
a2 = a1 + d
1 = a1 + d
a5 = a1 + 4d
7 = a1 + 4d
Subtracting the first equation from the second equation, u get:
6 = 3d
d = 2
Therefore, the common difference in the arithmetic sequence is 2.