Using (7), find the potential (r, ) in the unit disk r < 1 having the given

Using (7), find the potential Φ(r, θ) in the unit disk r < 1 having the given boundary values Φ(1, θ). Using the sum of the first few terms of the series, compute some values of Φ and sketch a figure of the equipotential lines.

Φ(1, θ) = α cos² 4θ