\input zb-basic
\input zb-matheduc
\iteman{ZMATH 2016b.00612}
\itemau{Miles, David}
\itemti{Improving an approximate formula.}
\itemso{Math. Sch. (Leicester) 40, No. 3, 29 (2011).}
\itemab
From the text: In a recent issue of this journal, [M. Rose, ``Miscellany", ibid. 39, No. 1, 27 (2010)] offered an interesting approximate formula: $\tan x =\frac{10+x}{100-x} (25\le x\le 65)$. But can we improve this formula without resorting to calculus? It seems reasonable to assume that a more accurate formula might take the form: $\tan x =\frac{x^2+Ax+B}{x^2+Cx+D}$.
\itemrv{~}
\itemcc{G60 N50}
\itemut{trigonometry; trigonometric functions; tangent; function values; approximate values; rational approximations; rational functions; percentage error}
\itemli{}
\end