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, .
This is the form of a geometric sequence.
Substitute in the values of and .
Rewrite as .
Multiply the exponents in .
Apply the power rule and multiply exponents, .
Apply the distributive property.
Multiply by .
Use the power rule to combine exponents.
Subtract from .