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## Homework Statement

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use richardson extrapolation to estimate the first derivative y=ln(x), x=5 using steps of 2, 1, 0.5. Four decimal points. obtain true relative error for the last estimate and comment on its value.

## Homework Equations

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deriv ln(x)=1/x

## The Attempt at a Solution

I know for step sizes of h and h/2 the formula is...

f'(x)=1/3 [ 4*[f(x+h/2)/h-f(x-h/2)/h] - f(x+h)/h-f(x-h)/h] + O(h^4)

but if im using steps h, h/2, h/4 the formula should be different, right?

or do you run the first step to find an approximation, then run it again using the next step?

Any help is appreciated!

Thanks