First, we find the general solution to the homogeneous equation 2y′′−2y′+25y=0. The characteristic equation is 2r2−2r+25=0. We can solve for r using the quadratic formula: r=2a−b±b2−4ac r=2(2)2±(−2)2−4(2)(25)=42±4−200=42±−196=42±14i=21±27i Since the roots are complex, r=α±βi, where α=21 and β=27. The general solution to the homogeneous equation is:
yh(x)=eαx(c1cos(βx)+c2sin(βx)) yh(x)=e21x(c1cos(27x)+c2sin(27x)) Next, we find a particular solution yp(x) to the non-homogeneous equation. Since the right-hand side is 5x−1, we assume a particular solution of the form yp(x)=Ax+B. Then, yp′(x)=A and yp′′(x)=0. Substituting these into the original equation:
2(0)−2(A)+25(Ax+B)=5x−1 −2A+25Ax+25B=5x−1 25Ax+(25B−2A)=5x−1 Equating coefficients:
25A=5⟹A=255=51 25B−2A=−1⟹25B−2(51)=−1⟹25B=−1+52=−53⟹B=−1253 So, yp(x)=51x−1253 The general solution to the non-homogeneous equation is the sum of the homogeneous solution and the particular solution:
y(x)=yh(x)+yp(x)=e21x(c1cos(27x)+c2sin(27x))+51x−1253