The given sequence is: 5, 25, 125, 625. To find the explicit rule for the nth term, let’s first observe the pattern in the sequence.
We can see that each term is a power of 5:
- The first term (n=1) is 5^1 = 5
- The second term (n=2) is 5^2 = 25
- The third term (n=3) is 5^3 = 125
- The fourth term (n=4) is 5^4 = 625
From this observation, we can conclude that the nth term of the sequence can be expressed explicitly as:
an = 5n
where n is the position of the term in the sequence. So, for any term in this geometric sequence, simply replace n with the term’s position to find its value.
For example:
- For n=1: a1 = 51 = 5
- For n=2: a2 = 52 = 25
- For n=3: a3 = 53 = 125
- For n=4: a4 = 54 = 625
This rule holds for all positive integer values of n.