请问这个图用matlab应该怎么画呢？

Question

已知Pst(x)的表达式，要求画x-Pst的图像和a-D的图像。

其他参数已经给出了，请大家指教。

Answer 1

你好！

tau = 1;
b=0.1;
alpha = 0.3;
lambda = 0.5;
D = 5.0;
a = 0.5;
N = 0.5;
x = 0:0.01:10;%这个你自己设置
beta = 1/sqrt(D*alpha*(1-lambda^2))*((2*lambda^2-1)*alpha/D*(tau*a*b-2*lambda*tau*b^2*...
sqrt(alpha/D)-b) + a*lambda*sqrt(alpha/D)+alpha*tau*b^2*lambda/b*sqrt(alpha/D));
gamma = 1/2/D*(a + alpha*tau*b^2/D + 2*lambda*sqrt(alpha/D)*(tau*a*b-2*lambda*tau*b^2*...
sqrt(alpha/D)-b))-1/2;
Pst = N*(1+tau*b*x).*(D*x.^2-2*lambda*x.*sqrt(D*alpha)+alpha).^gamma.*...
    exp(-tau*b^2/2/D*x.^2+(tau*a*b-2*lambda*tau*b^2*sqrt(alpha/D)-b)/D.*x...
    +beta*atan((D*x-lambda*sqrt(D*alpha))./sqrt(D*alpha*(1-lambda^2))));
figure(1);clf%画图
plot(x,Pst)
xlabel('x');ylabel('Pst')

tau = 1; b = 0.1; alpha = 3; 
afun = @(D, lambda) D + tau*b*lambda*sqrt(alpha*D);
D = 0:0.01:2.5;
a1 = afun(D, 0);
a2 = afun(D, 0.5);
a3 = afun(D, 1);
figure(2);clf
plot(D, a1,'r--', D,a2,'b-', D,a3,'m-.')
legend('\lambda=0','\lambda=0.5','\lambda=1')
xlabel('D');ylabel('a')