Solve the forced cauchy-euler equation 4t²y′′ - 4ty′ - y = 4√ t. Hint: guess y = tr. a) y = 1/4t² √t b) y = 1/4t² √t + C₁t + C₂t lnt c) y = 1/4t²√t + C₁t d) y = 1/4t² √t + C₁t²