[Rasch] Use of e in the Rasch model
yk0271 at yahoo.co.jp
Tue Sep 6 09:17:49 EST 2011
Hi Thomas, Thank you very much for your explanation. My background is psychology, and I learned basics of calculus when I was in high school. So, I can understand the concept of derivatives, but I did not know the derivative of f(x)=exp(X) is equal to f ' (x)=exp(x). That is very useful. So, is the use of exp in the Rasch model driven by this practicality? Is the function f(x)=exp(x) the only one whose derivative is equal to itself? Kenji
--- On Tue, 2011/9/6, Thomas Salzberger <thomas.salzberger at gmail.com> wrote:
And, of course, the derivation of [e to the power of x] is [e to the power of x], which is very convenient.
Thomas.Salzberger at gmail.com
Thomas.Salzberger at wu.ac.at
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