replacing symbolic coefficient in matrix with numeric one

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Joy Mondal 2019-7-11

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https://ww2.mathworks.cn/matlabcentral/answers/471231-replacing-symbolic-coefficient-in-matrix-with-numeric-one

评论： Walter Roberson 2019-7-12

syms s td a zf wf w
N =s^6*td^2 + 2*zf*s^5*td^2*wf + a*s^5*td^2 + 6*s^5*td + s^4*td^2*wf^2 + 2*a*zf*s^4*td^2*wf + s^4*td^2*wn^2 - k1*k2*s^4*td^2 + 12*zf*s^4*td*wf + 6*a*s^4*td + 12*s^4 + a*s^3*td^2*wf^2 + 2*zf*s^3*td^2*wf*wn^2 + 6*s^3*td*wf^2 + 12*a*zf*s^3*td*wf + 6*s^3*td*wn^2 + 6*k1*k2*s^3*td + 24*zf*s^3*wf + 12*a*s^3 + s^2*td^2*wf^2*wn^2 + 6*a*s^2*td*wf^2 + 12*zf*s^2*td*wf*wn^2 + 12*s^2*wf^2 + 24*a*zf*s^2*wf + 12*s^2*wn^2 - 12*k1*k2*s^2 + 6*s*td*wf^2*wn^2 + 12*a*s*wf^2 + 24*zf*s*wf*wn^2 + 12*wf^2*wn^2;
c=coeffs(N,s)
c=[ 12*wf^2*wn^2, 6*td*wf^2*wn^2 + 12*a*wf^2 + 24*zf*wf*wn^2, td^2*wf^2*wn^2 + 6*a*td*wf^2 + 12*zf*td*wf*wn^2 + 12*wf^2 + 24*a*zf*wf + 12*wn^2 - 12*k1*k2, a*td^2*wf^2 + 2*zf*td^2*wf*wn^2 + 6*td*wf^2 + 12*a*zf*td*wf + 6*td*wn^2 + 6*k1*k2*td + 24*zf*wf + 12*a, td^2*wf^2 + 2*a*zf*td^2*wf + td^2*wn^2 - k1*k2*td^2 + 12*zf*td*wf + 6*a*td + 12, 6*td + a*td^2 + 2*td^2*wf*zf, td^2]
a=-0.01;
wn=3.06309;
k1=0.5;
k2=-1;
td=0.1;
wf=3.43;
zf=0.175;