tikz求和

hbghlyj

In:=
     Sum[(i - 0.5)^2, {i, 0, 1, 0.2}]
Out:=
     0.7
在tikz中,

1. \documentclass[tikz]{standalone}
2. \begin{document}
3. \begin{tikzpicture}
4. \def\err{0}
5. \newcounter{i};
6. \loop
7. \pgfmathsetmacro{\err}{\err+(0.1*\value{i}-0.5)^2}
8. \ifnum \value{i}<9
9. \addtocounter{i}{2};
10. \repeat
11. \node at(0,0){\err};
12. \end{tikzpicture}
13. \end{document}

复制代码

输出0.70006