Originally Posted by

**harold** Hi CB,

Your derivative is of course right. But when choosing a "c" value to substitute in for x, dont you choose 1? In which I get .7954951286. Now to use the error formula from Simpson's Rule which is: $\displaystyle -\frac{h^5}{90}f^{iv}(c)$. I remember giving the error formula with something like b - a over 180 but that was the composite rule--I think we're using the regular rule (not composite) in which the error is the one above. When I compute everything, I get $\displaystyle 2.704857428$ but this can't be correct, the error should be small. (in the formula above, $\displaystyle h=x_2 - x_1 = x_1 - x_0 $ and the integral is from $\displaystyle x_2$ to $\displaystyle x_0$.

Also CB, when it says "Determine the number of subintervals n required to approximate the integral to within $\displaystyle 10^{-6}$ by using the composite trapezoidal rule," I can find it using math software myself but I'm stuck on the $\displaystyle 10^{-6}$ part...does that mean six decimal places must be correct or six digits or..?