Consider the following differential equation. y'' + 4y = sin 2t. The characteristic equation is a r² +b r + c =0. The roots of the characteristic equation is ± 2 i. Type the numerical value of a in the box. If we assume a particular solution using sin 2t and cos 2t, when the assumed particular solution is plugged into the given the differential equation, we reach a contradictory statement. We next try (tsin 2t, tcos 2t). The particular solution is computed as yp(t)= -C/4 tcos 2t. Type the value of C in the box (C is defined in the previous question)