Talk:Brahmagupta's interpolation formula

Blunder

The formula in the article is not right. The right formula is

$f(a)=f_{r}+t{\frac {D_{r}+D_{r-1}}{2}}+t^{2}{\frac {D_{r}-D_{r-1}}{2}}.$

Or, if you want to keep the formula, you should define

$D_{r}=f_{r}-f_{r-1}$.

МетаСкептик12 (talk) 14:20, 3 June 2015 (UTC)