matlab求偏导数 matlab如何求偏导

matlab求偏导步骤如下.1、第一步,双击打开matlab.2、第二步,定义两个变量a、b,在窗口中输入代码:syms a b.3、第三步,定义一个多元函数用于求偏导数,输.

syms x t; z = sin(x*t^2) ddt = diff(z, t) % 对t偏导 ddx = diff(z, x) % 对x偏导 the result is ddt = 2*t*x*cos(t^2*x) ddx = t^2*cos(t^2*x)

syms x yz = sin(x*y);d1 = diff(z, x);d2 = diff(d1, y);d2 = diff(d2, y) % 不加分号,输出最终结果

先说明一下dy/dx=dy/dz*dz/dx=dz/dx/(dz/dy),这样就可以求y对x的导数啦!syms x y z z=x+y-sqrt(x^2+y^2) diff(diff(z,y),x) //z对xy的二阶导 ans =1/(x^2+y^2)^(3/2)*y*x diff(z,x)/diff(z,y) //y对x的一阶导 ans =(1-1/(x^2+y^2)^(1/2)*x)/(1-1/(x^2+y^2)^(1/2)*y) 结果LZ在自己化简吧~

clearx_num=input('x=')y_num=input('y=')f=sym('x^2+y^2');dfdx=diff(f,'x')%对f求x偏导dfdy=diff(f,'y')%对f求y偏导dfdx_num=subs(dfdx,'x',x_num);dfdx_num=subs(dfdx_num,'y',y_num)dfdy_num=subs(dfdy,'y',y_num);dfdy_num=subs(dfdy_num,'x',x_num)

syms x y zz=solve('exp(z)-x*y*z','z')zdx=diff(z,x)zdxy=diff(zdx,y)结果:z =-lambertw(0, -1/(x*y))zdx =lambertw(0, -1/(x*y))/(x*(lambertw(0, -1/(x*y)) + 1))zdxy =lambertw(0, -1/(x*y))^2/(x*y*(lambertw(0, -1/(x*y)) + 1)^3) - lambertw(0, -1/(x*y))/(x*y*(lambertw(0, -1/(x*y)) + 1)^2)

同样使用函数diff,指定变量即可

先用SYMS 定义你的变量,然后定义你的函数,时候使用 diff('函数式','a')对a求偏导

用matlab只能得到数值解,没办法得到具体的解析式

Your question is very difficult indeed. So far I cannot find any helpful information . So my personal suggestion is to copy the code to your Matlab and the code should display .