.1623Р>> angle(a)Рans =Р -0.5880 -1.0304 -1.8338 -1.2490Р即复数的实部和虚部、共轭复数、模与辐角上所示Р16. (1)求方程的所有根;Р (2)求微分方程的一般解。Р解:(1)用MATLAB输入:Р >> z=solve('z^3+8=0','z')Р输出:Рz =Р -2Р 1 - 3^(1/2)*iР 3^(1/2)*i + 1Р即方程的根为Р(2) 用MATLAB输入:Р >> y=dsolve('D3y+8*y=0','x')Р输出:Рy =РC1/exp(2*x) + C2*exp(x)*cos(3^(1/2)*x) + C3*exp(x)*sin(3^(1/2)*x)Р即微分方程的一般解为Р用MATLAB画图如下:Р输入:Р(1)取C1,C2,C3均为1:Р>> x=[-10:0.01:10];Р>> y=exp(-2*x)+exp(x).*sin(3^(1/2)*x)+exp(x).*cos(3^(1/2)*x);Р>> plot(x,y)Р(2)取C1,C2,C3均为2:Р >> x=[-10:0.01:10];Рy=2*exp(-2*x)+2*exp(x).*sin(3^(1/2)*x)+2*exp(x).*cos(3^(1/2)*x);Рplot(x,y)Р(3)取C1为5,C2、C3均为1:Р >> x=[-10:0.01:10];Рy=5*exp(-2*x)+exp(x).*sin(3^(1/2)*x)+exp(x).*cos(3^(1/2)*x);Рplot(x,y)Р Р(4)取C1为-2,C2、C3均为1:Р >> x=[-10:0.01:10];Рy=-2*exp(-2*x)+exp(x).*sin(3^(1/2)*x)+exp(x).*cos(3^(1/2)*x);Рplot(x,y)
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