I know how to put a resized arrow tip at one end of a dashed line, but not at both ends. See the image below.
\documentclass[pdftex,12pt,a4paper,english,dutch,leqno]{article}
\usepackage[top=1cm,right=1cm,bottom=1cm,left=1.5cm,noheadfoot]{geometry}
\usepackage{babel}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{tikz}
\usetikzlibrary{arrows,decorations.markings,patterns,calc}
\begin{document}
{\begin{tikzpicture}[>=angle 60]
\draw[<->,line width=0.15mm,dashed,dash pattern=on 1mm off 0.5mm] (0,0.5)--(5,0.5) node[right] {Default arrows are too small};
\draw[line width=0.15mm,dashed,dash pattern=on 1mm off 0.5mm,decoration={markings,mark=at position 1 with {\arrow[line width=0.1mm,scale=1.5]{>}}},postaction={decorate}] (0,0)--(5,0) node[right] {How to put arrows like this at both ends ?};
\end{tikzpicture}
\end{document}




mark=between positions 0 and 1 step 1. – Peter Grill Oct 16 '12 at 16:21decoration={markings,mark=at position 0 with {\arrow[line width=0.1mm,scale=1.5]{<}},mark=at position 1 with {\arrow[line width=0.1mm,scale=1.5]{>}}},postaction={decorate}– Alain Matthes Oct 16 '12 at 16:22