What is the 8th term of the geometric sequence –1, 4, –16, …?
The 8th term is
A geometric sequence is a sequence of the form
Because of this, given any two successive terms of the sequence, you can find
In the given sequence, then, we can find the ratio by dividing the second term by the first:
Finally, to obtain the 8th term in the sequence, we can either calculate the term by multiplying successive terms by the ratio repeatedly, or directly as
In either case, we arrive at the 8th term being