, ,

This is a geometric sequence since there is a common ratio between each term. In this case, multiplying the previous term in the sequence by gives the next term. In other words, .

Geometric Sequence:

This is the form of a geometric sequence.

Substitute in the values of and .

Apply the product rule to .

One to any power is one.

Combine and .

Substitute in the value of to find the th term.

Subtract from .

Raise to the power of .

Divide by .

Find the 4th Term 400 , 200 , 100