(a) Express \(f(x)\) in partial fractions:
Assume \(f(x) = \frac{A}{1-x} + \frac{B}{2+3x} + \frac{C}{(2+3x)^2}\).
Using a correct method for finding coefficients, we find:
\(A = 1\), \(B = -1\), \(C = 6\).
(b) Obtain the expansion of \(f(x)\):
Use a correct method to find the first two terms of the expansion of each partial fraction:
\(\frac{1}{1-x} = 1 + x + x^2 + \ldots\)
\(\frac{1}{2+3x} = \frac{1}{2}(1 - \frac{3}{2}x + (\frac{3}{2}x)^2 + \ldots)\)
\(\frac{1}{(2+3x)^2} = \frac{1}{4}(1 - 3x + \frac{9}{4}x^2 + \ldots)\)
Substitute back into the partial fractions and simplify:
\(f(x) = (1 + x + x^2) + \left(-\frac{1}{2} - \frac{3}{4}x - \frac{9}{8}x^2\right) + \left(\frac{6}{4} + \frac{18}{4}x + \frac{81}{8}x^2\right)\)
Combine and simplify to get:
\(f(x) = 2 - \frac{11}{4}x + 10x^2\).