DOC《习题：》

a*t^2+b*t+c=0'

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) r = [ 1/2/a*(-b+(b^2-4*a*c)^(1/2))] [ 1/2/a*(-b-(b^2-4*a*c)^(1/2))] 17, 用符号计算验证三角等式:(应用syms,simple) sin((1)cos((2)-cos((1)sin((2) =sin((1-(2) >

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syms phi1 phi2;

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y=simple(sin(phi1)*cos(phi2)-cos(phi1)*sin(phi2)) y = sin(phi1-phi2) 18, 求矩阵的行列式值、逆和特征根. >

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syms a11 a12 a21 a22;

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A=[a11,a12;

a21,a22] >

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AD=det(A)行列式 >

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AI=inv(A)逆>

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AE=eig(A)特征值 A = [ a11, a12] [ a21, a22] AD = a11*a22-a12*a21 AI = [ -a22/(-a11*a22+a12*a21), a12/(-a11*a22+a12*a21)] [ a21/(-a11*a22+a12*a21), -a11/(-a11*a22+a12*a21)] AE = [ 1/2*a11+1/2*a22+1/2*(a11^2-2*a11*a22+a22^2+4*a12*a21)^(1/2)] [ 1/2*a11+1/2*a22-1/2*(a11^2-2*a11*a22+a22^2+4*a12*a21)^(1/2)] 19, 因式分解: >

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