Graphics, Figures & Tables ⇒ tikZ | Arc in an Angle

[sachinrajsharma]

Hi,

I want to draw an arc at the point P(\alpha) which is making an angle with center O.

Please help how to make an arc at this particular point. I am attaching the source file as well as PDF file for reference.


Regards,
Sachin Sharma

[ibaldwin]

Hi,

Sorry for probably not the best answer, but how about extending (or reproducing) one of the existing arcs to reach the "O" point ?

Say, instead of \draw (14mm,0mm) arc (180:210:6mm) you may want to extend the radius to reach the O point, perhaps \draw (14mm,0mm) arc (180:210:20mm).


Ian

[localghost]

[…] I want to draw an arc at the point P(\alpha) which is making an angle with center O. […]

Which point is going to be the center of this arc? In which point does this arc end?

Your sketch can be simplified a bit by the tkz-euclide package.

Code: Select all

\documentclass[11pt]{standalone}
\usepackage[T1]{fontenc}
\usepackage{tkz-euclide}
\usetkzobj{all}

\begin{document}
  \begin{tikzpicture}[scale=2]
    \tkzDefPoint (0,0){O}
    \tkzDefPoint (2,0){A}
    \tkzLabelPoints[left](O)
    \tkzDrawCircle[R](O,1cm)
    \tkzTangent[from with R=A](O,1cm) \tkzGetPoints{T1}{T2}
    \tkzDrawLines[add=0 and 0](O,T1 O,T2 O,A)
    \tkzDrawLines[add=0 and 0.5](A,T1 A,T2)
    \tkzDrawArc[R with nodes,](A,0.5)(T1,T2)
    \draw (T1) node[above right] {$P(\alpha)=(a\,\cos\alpha,a\,\sin\alpha)$};
    \draw (T2) node[below right] {$Q(\alpha)=(a\,\cos\beta,a\,\sin\beta)$};
    \draw (A) +(165:0.6) node {$\alpha$} (A) +(195:0.6) node {$\beta$};
  \end{tikzpicture}
\end{document}

Thorsten