I am making a multiple choice problem. (Here, I display two of the choices.) I am trying to plot parabolas using pgfplots. Why is TikZ not compiling my code? I put a % in front of the parabolas that I would like plotted so that TikZ will compile the code.
Also, I would like the picture to be flush against the left margin. I typed \hspace{\fill} after the end of the tikzpicture environment.
\documentclass{amsart}
\usepackage{tikz}
\usetikzlibrary{calc,angles,positioning,intersections}
\usepackage{pgfplots}
\pgfplotsset{compat=1.11}
\begin{document}
\begin{tikzpicture}
%These four commands give commands to draw a rectangle in which the graphs are to be drawn.
\draw[gray,dashed,line width=0.1pt,name path=top] (-6,4.25) -- (6,4.25);
\draw[gray,dashed,line width=0.1pt,name path=right] (6,0) -- (6,4.25);
\draw[gray,dashed,line width=0.1pt,name path=bottom] (-6,0) -- (6,0);
\draw[gray,dashed,line width=0.1pt,name path=left] (-6,0) -- (-6,4.25);
%These commands place the letters indicating the choices.
\node[left] (a) at (-6,4) {$\mathrm{a.)}$};
\node[left] (b) at (1,4) {$\mathrm{b.)}$};
%These commands place the axes for the graphs.
\draw[draw=gray!30,latex-latex] (-3.5,4) +(0,0.5cm) node[above right] {$y$} -- (-3.5,1) -- +(0,-0.5cm);
\draw[draw=gray!30,latex-latex] (-5.5,2) +(-0.5cm,0) -- (-1.5,2) -- +(0.5cm,0) node[below right] {$x$};
%\addplot[samples=201,domain=-3.75:-3.25,blue] {-4*(x + 3.5)^(2) + 1.5};
%These commands plot the second parabola on the Cartesian plane.
\draw[draw=gray!30,latex-latex] (3.5,4) +(0,0.5cm) node[above right] {$y$} -- (3.5,1) -- +(0,-0.5cm);
\draw[draw=gray!30,latex-latex] (1.5,2) +(-0.5cm,0) -- (5.5,2) -- +(0.5cm,0) node[below right] {$x$};
%\addplot[samples=201,domain=-2.75:-2.25,blue] {(x - 3.5)^(2) + 2.5};
\end{tikzpicture}
\hspace{\fill}
\end{document}


axisenvironment. Instead of mixingtikzandpgfplots, use onlypgfplotsto draw every thing – May 02 '15 at 00:21\addplot {(x - 3.5)^(2) + 2.5};. Why are straight lines plotted? I think the last edit is to remove the surrounding squares. – user143462 May 02 '15 at 00:53