what is the function of this iteration

the figure on this link. http://salotungo.blogspot.de/

an the function is: http://salotungo.blogspot.de/2012/11/blog-post.html#more

it is better we see it directly.

i want thelast data is n1 n2 n3 n4 so i can make plot directly. recently i did it manually one by one.

thx

[Image Analyst]

I don't know what this means: "i want thelast data is n1 n2 n3 n4" And what did you do manually?

[uncung fgv]

n1,2,3 I mean the last calculation of (y3-y2)/(y2-y1)=n1;

(y4-y3)/(y3-y2)=n2;

and soon n3..7

i did it manually:

by calculating:

every difference of y1..7

and devide them also one another, one by one from plot to plot.

is there any simple function to calculate n1..7?

thx.

[Daniel Shub]

I am closing this question until the OP adds details.

[uncung fgv]

the detail:

my problem is its iteration. manually it is ok. but i have many plots ánd datas.

i have a figure that have many plots within.

i want:

(y3-y2)/(y2-y1)=n1

(y4-y3)/(y3-y2)=n2

(y5-y4)/(y4-y3)=n3

(y6-y5)/(y5-y4)=n4

and soon until n7

the function of the figure is

w=8;

x=2;

a=0.2;

w=(0:0.3:3);

k=1; 1, 2,3,4,5,6,7 ; variable change

S=[1-exp(-a.*x.*k.*w)];

figure(1)

plot(w,S,'-+');

xlabel('w');

ylabel('S');

hold on

if we run this with k= 1, 2,3,4,5,6,7 we will find plots at one figure. and i want to calculate n1..n7 as above.