6.26.3 Can you answer these questions?

6.26.3.1 How to define a derivative of a function at some point?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233672

Consider a function 
 derivative[x_]:=D[Sin[x],x] 
 
When calling it with some argument, like derivative[2], instead of $\cos(x)$ it gives me $\partial_{2}\sin(2)$. Is ... 
[calculus-and-analysis] [syntax]
 

asked by John Taylor https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=41058 1 vote

6.26.3.2 Insufficient memory problem in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233470

I am trying to initialize a 48600 x 48600 packed array from a sparse matrix and a diagonal matrix in Mathematica 8. If S1 is a sparsearray of that size then and S2 is list of 48600 length, then I am ... 
[memory] [sparse-arrays]
 

asked by Roopayan Ghosh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=54433 4 votes

6.26.3.3 Classify; how UtilityFunction matrix is applied to resolve prediction?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233669

I can't find any explanation about the details of the real computation, please anybody knows? 
... 
[machine-learning]
 

asked by pablo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61453 1 vote