- #1

vinh pham

- 1

- 0

_{0}r) respect to k in order to calculate exp(-ik

_{1}r) by using Taylor expansion:

exp(-ik

_{1}r) = (exp(-ik

_{0}r))

^{(0)}+(k

_{1}-k

_{0})(exp(-ik

_{0}r))

^{(1)}/1! + (k

_{1}-k

_{0})

^{2}(exp(-ik

_{0}r))

^{(2)}/2! + ...

This expansion converges when the value of r is relative low (0.3 - 1.2). However, when r grows with larger value (100-1000), the expansion does not converge any more.

k

_{0}= 21

k

_{1}= 27

Is there any solution to find exp(ik

_{1}r) by using Taylor expansion for larger r?

Thank you very much