@tomleslie 

how you do combination like printf(..) = newvariable(i)

become new variable 1 = 30

i got result like new varriable 1 

                                                  () = 30

@gkokovidis how to make one variable secant line, can you give me an example,thanks

just one variable

@Carl Love 
Fib:= proc(n::nonnegint, k::nonnegint)
option remember;
    if k > n then 0
    elif n=0 or n=k or k=0 then 1
    else thisproc(n-1,k-1) + thisproc(n-1,k)
    fi
end proc
:
CodeTools:-Usage(Fib(25,12));

The one you wrote at last question, sorry for inconvenience

@Carl Love  How you gonna use this equation to find the 100th Fibonacci number?