MATLAB: Find roots through iterative method

iterationrootstranscendent equation

I need to find 3 roots of an equation (e^x=3*x^2 – transcendent equation) through the iteration method in Matlab. What algorithm should I use?

Best Answer

You can use FZERO, e.g.,

   >> f=@(x) exp(x)-3*x.^2
   >> [xroot,res]=fzero(f,.1)

You will need to provide an initial guess of each of the three roots, which you can obtain by plotting the function f(x)=e^x-3*x^2

Related Solutions

MATLAB: Need to solve e^x=3*x in tho ways

The roots of f(x)=exp(x)-3*x are the same as solving exp(x)=3*x.

MATLAB: Multiple roots formula with Matlab

I think your formula shoud be

First define your function and its first two derivatives in Matlab

f = @(x) x.^4- 6*x.^3 + 12*x.^2 - 10*x +3; % function
fp = @(x) ...;                             % first derivative here
fpp = @(x) ...;                            % second derivative here

Set an initial guess for x and a tolerance. Initialise an error measure and an iteration number. e.g:

x = 5; %initial guess 
tol = 10^-6;
err = 1;
its = 0;

Then use a while loop

while err>tol && its<100
    xold = x;
    x = ... put your iteration formua here 
    err = abs(x-xold); 
    its=its+1;
end

Display your result

disp(x)

Be careful not to use an initial guess that makes fp equal zero, or the routine will fail!

Best Answer

Related Solutions

MATLAB: Need to solve e^x=3*x in tho ways

MATLAB: Multiple roots formula with Matlab

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