The general solution of the second order nonhomogeneous linear equation can be expressed in the form
y=yc+Ywhere Y is any specific function that satisfies the nonhomogeneous equation, and yc=C1y1+C2y2 is a general solution of the corresponding homogeneous equation
y′′−3y′+2y=0 The Characteristic Equation
r2−3r+2=0(r−1)(r−2)=0 r1=1,r2=2
The general solution of the corresponding homogeneous equation is
yc=C1ex+C2e2x Use Method of Undetermined Coefficients
Y=Ae−x+Bcos(3x)+Csin(3x)
Y′=−Ae−x−3Bsin(3x)+3Ccos(3x)
Y′′=Ae−x−9Bcos(3x)−9Csin(3x)
Ae−x−9Bcos(3x)−9Csin(3x)+
+3Ae−x+9Bsin(3x)−9Ccos(3x)+
+2Ae−x+2Bcos(3x)+2Csin(3x)=3e−x−10cos(3x) 6A=3=>A=21
−7B−9C=−10
9B−7C=0
B=137,C=139
Y=21e−x+137cos(3x)+139sin(3x)
y=C1ex+C2e2x+21e−x+137cos(3x)+139sin(3x)
y(0)=1:
1=C1+C2+21+137
y′(0)=2:
y′=C1ex+2C2e2x−21e−x−1321sin(3x)+1327cos(3x)
2=C1+2C2−21+1327
1=C2−1+1320
C2=136
C1=−21
yp=−21ex+136e2x+21e−x+137cos(3x)+139sin(3x)
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