# How to draw the following pictures in LaTex?

I want to draw the following pictures, but I don't know how to draw it. Could anyone help me?　Thank you very much.

• Could you add what you have tried so far? – user156344 Apr 13 at 2:59
• We generally frown on "how do I draw this picture" type questions. They don't show us that you want to learn TeX (or you would have gotten a good portion of the work done already). They don't give us anything to start from, and make us do all the boring work on our own. They don't show us what you already understand, so we'll be left trying to explain everything. And they can't help future users, since no one can get this question as a search result. – Teepeemm Apr 13 at 3:16

Anyway I'm currently in free time so this is some quick codes. For most accurate figures, you still have to edit it a bit.

\documentclass[tikz]{standalone}
\begin{document}
\begin{tikzpicture}
\draw[->] (-1.5,0) edge (3,0) (0,-1.5) edge (0,3);
\path (3,0) node[right] {$x$} (0,3) node[above] {$y$};
\draw[very thick,<->] (30:2) node[right] {$(a,b)$} -- (0,0) -- (-30:2) node[right] {$(a,-b)$};
\end{tikzpicture}
\end{document}


\documentclass[tikz]{standalone}
\usetikzlibrary{positioning,quotes,angles}
\begin{document}
\begin{tikzpicture}
\draw[->] (-1.5,0) edge (3,0) (0,-1.5) edge (0,3);
\path (3,0) node[right] {$x$} coordinate (x) (0,3) node[above] {$y$};
\draw[very thick,<->] (30:2) coordinate (a) node[right] {$(\cos\theta,\sin\theta)$} -- (0,0) coordinate (o) -- (120:2) node[above left=0pt and -3em] {$(\sin\theta,-\cos\theta)$};
\pic[draw,"$\theta$",angle radius=.7cm,angle eccentricity=1.3] {angle=x--o--a};
\end{tikzpicture}
\end{document}


\documentclass[tikz]{standalone}
\begin{document}
\begin{tikzpicture}
\draw[->] (-.75,0) edge (3,0) (0,-.75) edge (0,3);
\path (3,0) node[right] {$x$} coordinate (x) (0,3) node[above] {$y$};
\draw[very thick,<->] (0,1.5) node[left] {$(0,1)$} |- (1.5,0) node[below] {$(1,0)$};
\draw (0,1.5) -| (1.5,0);
\end{tikzpicture}
\end{document}


\documentclass[tikz]{standalone}
\begin{document}
\begin{tikzpicture}
\draw[->] (-.75,0) edge (3,0) (0,-.75) edge (0,3);
\path (3,0) node[right] {$x$} coordinate (x) (0,3) node[above] {$y$};
\draw[very thick,<->] (1.5,1.5) node[above] {$(0,1)$} -- (0,0) -- (1.5,0) node[below] {$(1,0)$};
\draw (1.5,1.5) -- (3,1.5) -- (1.5,0);
\end{tikzpicture}
\end{document}