How to do interpolation with data in descending arrangement

[ptc-4630534]

Hi Experts,

i have a set of data for creating a normal XY graph. However as for the X axis, the data is not in the ascending form. Instead it is descending. the question is how can i perform an interpolation with this arrangement in mathcad. Anyway i'm still using mathcad14 FYI.

Appreciate your assistance on the matter.

BTW attached is the extracted section on what i've meant

Thank you in advance

Regards

-Akmal-

[ValeryOchkov · Accepted solution]

See the attach

[ptc-4630534]

Dear Valery,

wow......it is impressive...

FYI i'm a beginner level in mathcad though have use it for few years now. By looking at the spreadsheet that you have ammended, i'm not that clear on how to tackle the problem if in future i'm facing the same situation. Appreciate if you could briefly explain on steps taken and below question for my understanding.

1) from the amended spreadsheet, the values in column <0> of table GraphA9 is different from earlier sent, how do you calculate it? and why do we need to do that

2) what does csort do and why do we need to do that?

3) in the x range, there's a division of 30000, how do we get this? does other values will affect on the results?

Thank you again

Regards

-Akmal-

[ValeryOchkov]

1) from the amended spreadsheet, the values in column <0> of table GraphA9 is different from earlier sent, how do you calculate it? and why do we need to do that

We need to have X values in increasing order.

2) what does csort do and why do we need to do that?

Read please the help on the csort (column sort) function.

3) in the x range, there's a division of 30000, how do we get this? does other values will affect on the results?

Change please 30000 to 3000 or 300 and see the plot.