Pls pls pls help me with the two ratio questions

Do u just plot the numbers on the graph like (1,

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

An angle that measures between 90 and 180° is called a(,