Show that if p(z)=an (2-21) (222) ¹²... (z-z,), then the partial fraction expansion of the logarithmic derivative p'/p is given by p'(z) d₁ d₂ dr + ++ P(z) Z-21 z-22 z - Zr [HINT: Generalize from the formula (fgh) = f'gh+fg'h+fgh'.]