If x values are: 10, 20, 30, 40, 50(adsbygoogle = window.adsbygoogle || []).push({});

corresponding y values are:20, 65, 180, 390, 505

then what is y value at x=25.

I was having an argument with maths sir. I was saying to take x0 as 10 to get the answer as 107.14, which is correct application of formula,

but our maths sir said that we should take x0 as 20, since it is closest value to 25.

According to me in formula we should take first value incase if it is not backward interpolation formula as otherwise then we are missing then the 4th difference in difference table.

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# X0 value for Newton's forward interpolation formula

**Physics Forums | Science Articles, Homework Help, Discussion**