Matlab [function derivation]

Catalog

One 、 Derivative function

  Find the zero point of the derivative function

  Find the higher derivative

  Derivative of compound function

  Implicit derivative

  Derivation of parametric equation

  Find the zero of a function

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One 、 Derivative function

Derivative function diff, Replace variable subs

syms x 
f=x^(1/2)+sin(x);
diff(f)

 

  Find the zero point of the derivative function

syms x 
df=3*x^2-6*x+3
s=solve(df)

  Find the higher derivative

syms x 
df=3*x^2-6*x+3
z=diff(df,2)

  Derivative of compound function

syms x
f=log(cos(exp(x)));
diff(f)

  Implicit derivative

Here we need to use the implicit function derivation formula

% Declare two symbolic variables 
syms x y
% Generate our function 
f=exp(y)+x*y+exp(x);
% Yes x Finding partial derivatives 
dfx=diff(f,x);
% Yes y Finding partial derivatives 
dfy=diff(f,y);
% Derivation formula of implicit function 
dyx=-dfx/dfy

  Derivation of parametric equation

syms t
x=t-sin(t);
y=1-cos(t);
% seek dx/dt
dx=diff(x,t);
%dy/dt
dy=diff(y,t);
dy/dx

  Find the zero of a function

Use fzero( function , Range ） Then we can find the zero point in this range

syms x
[email protected](x) exp(x)+sin(x)+x;
fzero(f,[-1,1])