6 Select the correct answer for each question (only one per question) . If you select an answer and change your mind make sure you uncheck your previous answer. 1. Find the most suitable form ( with minimum amount of terms ) for a particular solution of y"+ ty = - 5et+ tsin ( It ) if the method of undetermined coefficients is used. 1 A . Yp = Aert +t ( Bt + ( ) sin( zt ) + + ( D+ + E ) cos ( it ) B. YP = Ae + Btsin ( 2t ) + Ct cos ( It ) C . YP = Aert + B sin ( 2t ) + (cos ( 2t) D. YP = Aert+ Btsin (2t ) E. YP = Aert+ ( Bt + ( ) sin ( It) + (Dt+E) cos( it) F. None of the above 2. The phase portrait of the system =y dy - x consits of A. circles B. lines through the origin c. hyperbolas D. ellipses E. Parabolas F. None of the above