Final answer:
The given sequence does not exhibit a consistent geometric pattern, which is necessary for determining a formula for the nth term of a geometric sequence.
Step-by-step explanation:
The question asks for the equation of the nth term in a geometric sequence. The given sequence is somewhat confusing because the numbers do not seem to follow a clear geometric pattern, possibly due to typographical errors in the sequence.
Typically, a geometric sequence follows a pattern where each term after the first is found by multiplying the previous term by a constant called the common ratio. However, the provided sequence (1, 2, 3, 4, 100, -50, 25, -12.5) seems inconsistent, as the ratio between consecutive terms is not constant.
A meaningful nth term equation requires a sequence with a consistent pattern, such as a common ratio in a geometric sequence.