In physics classes, on this StackExchange and even in blogs the sum 1+2+3+4+⋯=−112 has been under the microscope.
As a consequence of the trapezoid rule, the error to the Riemann sum is bounded by the second derivative.
∫N0f(x)dx=12f(0)+f(1)+⋯+f(N−1)+12f(N)+O(N‖f‖˙C2)
Letting f(x)=(1−x/N)+ we get ∑N−1i=01=−12+∫N01dx+O(1).
I am wondering what happen if we use the Simpson rule:
∫N0f(x)dx=13(f(0)+4f(1)+2f(2)+⋯+4f(N−1)+f(N))+O(N||f||˙C4)
Now we plug in f(x)=(1−x)+ and get
13(4+2+4+2+⋯)=−13+∫N0f(x)dx+O(N−3)
Is that still consistent with the other types of sums you get from Euler-Macularin type summation methods?
No comments:
Post a Comment