Approximate (Numerical) Integration
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Suppose that both the ln and log buttons
have fallen off your calculator,
but you desperately need to compute
a decimal approximation of \(\ln(4)\).
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First recall that the \(\ln\) function
is defined in terms of an integral.
Write down the definite integral that equals \(\ln(4)\).
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Use the midpoint rule to estimate
the value of \(\ln(4)\) with six equal subintervals.
Then use the trapezoid rule to estimate \(\ln(4)\),
and then use Simpson’s rule.
How much better does each approximation get?
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Can you write a computer program to approximate
the decimal presentation of \(\ln(4)\)?
As a reference, to check your program,
past mathematicians have computed
\[\ln(4) \approx 1.3862943611198906188344642429163531361510002687\,.\]