The radius of a circle is 2x. What is its diameter?

Scale factor of 2 is used to enlarge a figure as shown below the area of is 18 in.²

Proceed as in example 3 in section 6.1 to rewrite the given expression using a single power series whose general term involves xk. ∞ n(n − 1)cnxn − 2 n = 2 − 4 ∞ ncnxn n = 1 + ∞ cnxn n = 0

We just started the introduction into circles and i have no idea how to do this.