y1dy1+y2dy2+y3dy3=(sin2x+cos2x+x32−x3)dx
ln(y1y2y3)=x2−1+C
ln(y1(x)y2(x)y3(x))=x2−1+C
ln(5⋅31⋅5e3)=x2−1+C
∴C=0
y1(x)y2(x)y3(x)=ex2−1
limx→0e3xsinxex2−1+2x
limx→0e3x+x21sinx1+limx→0e3xsinx2x
limx→0e3x⋅xsinx⋅x1ex211+2
=0+2{limy→∞yey2=1ey2⋅2y=∞}
=2