How to formulate the summation of sequence number

I have a sequence data between X and Y. In general Y is X summation

X Y

6.84 6.84

12.04 18.88

9.47 28.35

8.53 36.88

6.91 43.79

2.93 46.72

0.82 47.54

0.54 48.08

0 48.08

0 48.08

Y1=X1

Y2=X1+X2

Y2=X1+X2+X3

how to develop the function.

Thanks

[Walter Roberson]

cumsum

[Skydriver]

Can you tell me in detail ?

[Walter Roberson]

Tommy's code has the entire detail of the code.

Answer 1

[Tommy]

Try

Y = cumsum(X)

[Skydriver]

No, it is not my expectation.

[Walter Roberson]

If agreement to within roundoff error is not good enough, then what do you require?

[Skydriver]

Thank you it works know