matlab的微积分编程问题

Question

求解该函数在两种情形下对应点x处的二阶导数值，请给出思路与程序，谢谢

Answer 1

syms a x
y = a*exp(x)/sqrt(a+x^2);
y_1 = diff(y, x);
y_2 = diff(y_1, x);

a1 = 2;
x1 = 3*a1;
y2_1 = double(subs(y_2, [a, x], [a1, x1]));

a2 = 3;
x2 = 2*a2;
y2_2 = double(subs(y_2, [a, x], [a2, x2]));

disp(['a=2, x=3a, y2 = ' num2str(y2_1)]);
disp(['a=3, x=2a, y2 = ' num2str(y2_2)]);