%求解Lame波反對稱部分的基本模態(tài)Ao
format long
syms c;   %定義速度c為符號函數(shù)
kh=0.4   %k為波數(shù)，h為總的板厚
cd=5790;cs=3200; %cd為縱波波速，cs為橫波波速
y1=4*tanh(kh/2*(1-(c/cs)^2)^(1/2))*(1-(c/cd)^2)^(1/2)*(1-(c/cs)^2)^(1/2);
y2=(2-(c/cs)^2)^2*tanh(kh/2*(1-(c/cd)^2)^(1/2));
c=[400;700];
eps=1e-12;
xx=[];
for i=2:2
    a=c(i-1);b=c(i);
    c=(a+b)/2;
    while (subs(y1-y2)~= 0) & ((b-a)>eps)
        c=(a+b)/2;
        fa=4*tanh(kh/2*(1-(a/cs)^2)^(1/2))*(1-(a/cd)^2)^(1/2)*(1-(a/cs)^2)^(1/2)-(2-(a/cs)^2)^2*tanh(kh/2*(1-(a/cd)^2)^(1/2));
        fb=4*tanh(kh/2*(1-(b/cs)^2)^(1/2))*(1-(b/cd)^2)^(1/2)*(1-(b/cs)^2)^(1/2)-(2-(b/cs)^2)^2*tanh(kh/2*(1-(b/cd)^2)^(1/2));
        fy=4*tanh(kh/2*(1-(c/cs)^2)^(1/2))*(1-(c/cd)^2)^(1/2)*(1-(c/cs)^2)^(1/2)-(2-(c/cs)^2)^2*tanh(kh/2*(1-(c/cd)^2)^(1/2));
        if fa*fy < 0
            b=c;
        else
            a=c;
        end
    end
    xx=[xx;c];
    xx=[xx;c]
    m=subs(y1-y2)
end