How to write a code for an equation in such a way that it add previous results repetitively?

Hi

I want calculate distance between to points as:

X1 = X(1:end-1); X2 = X(2:end);

Y1 = Y(1:end-1); Y2 = Y(2:end);

xi = 5.55e5;

x = xi + sqrt((X2-X1).^2 + (Y2-Y1).^2);

But I want like say first value of x is = xi (5.55e5) and in the second value of x, xi will be added and in the next value the previoous one will be add and so on... I mean after first value equation of x will move in a way that the previous one will be added into the results. How can I write x equation in matlab? For example

if X = [2 3 4 5 6 7 8 9];

X1 = X(1:end-1); X2 = X(2:end);

xi = 5.55e5;

Now if I compute x as (assuming Y2 = Y1, and Y2-Y1 is 0.

x1 = 5.55e5 + sqrt(3 - 2).^2

x1 = = 555001;

x2 = x1 + sqrt(4 - 3).^2

and so on....

How to write in MATLAB equation/code?

[Torsten]

Unclear.

Give an example with numbers, e.g. for X = [1 2 3 4], Y = [5 6 7 8].

[Nisar Ahmed]

@Torsten edited

[Torsten]

And Y has disappeared in the example ?

[Nisar Ahmed]

@Torsten I make it more clear now

Answer 1

[Torsten]

xi = 5.55e5;
X = ...;
Y = ...;
x = [xi,sqrt((X(2:end)-X(1:end-1)).^2 + (Y(2:end)-Y(1:end-1)).^2)];   % assumes X and Y are row vectors
x = cumsum(x)