MATLAB: HOW DO I ADD DIVSIONBY ZERO EQUATION FOR MATLAB

 Speed=C/Distance/Time=0
 Distance infinite space = Pi/0

D Hopitals rule means you can divide By 0 when it is infinity. As speed goes to C the limite goes to zero T. That proves infinite not finite space. How do I reprogram matlab to ignore divison by zero errors and give C as the answer a finite speed.

Best Answer

You could do some sort of thresholding when the limit starts to take hold accurately enough:

if C>threshold
     %Use L'Hospital's rule 
end

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MATLAB: How can i use L’hospital rule i.e sin(x)/x for x tends to zero

By convention, 0/0 evaluates to NaN.

To be absolutely formal (if a bit kludgy) about using L’Hospital's rule in this situation:

fderiv = @(f,x) (f(x+eps)-f(x))/eps;                    % Derivative of a function
xderiv = @(x) ((x+eps)-x)/eps;                          % Derivative of an expression
for n = 0:7
    x(n+1)=sin((pi*n)/2)./(pi*n);
    if isnan( x(n+1) )                                  % Test for ‘NaN’
        x(n+1) = fderiv(@sin, pi*n/2)./(xderiv(pi*n));  % L'Hospital's Rule
    end
end

There are better and more numerically stable derivative expressions (such as the five-point algorithm), but this will do for an illustration.

Also, using L'Hospital's rule,

x=sin((pi*n)/2)./(pi*n)

will be 1 at n=0, however:

x=(sin(pi*n)/2)./(pi*n)

with the fderiv call then becoming:

x(n+1) = (fderiv(@sin, pi*n)/2)./(xderiv(pi*n));

will be 0.5 for n=0.

MATLAB: Help with MATLAB Code – Plot is ignoring 0 value

Actually the zero value is undefined, because of a division by zero. You can use isnan to replace this with 0.

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MATLAB: How can i use L’hospital rule i.e sin(x)/x for x tends to zero

MATLAB: Help with MATLAB Code – Plot is ignoring 0 value

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