Trig Values of -120 degrees

<BODY LANG="EN" > <HR><center> <table border=1> <td><A HREF="node32.html"><img height=36 width=36 alt="PREVIOUS" src="/UCESIcons/tools/previous.gif"></A></td> <td><A HREF="node31.html"><img height=36 width=36 alt="UP" src="/UCESIcons/tools/up.gif"></A></td> <td><A HREF="node34.html"><img height=36 width=36 alt="NEXT" src="/UCESIcons/tools/next.gif"></A></td> <td><a href="contents-node33.html"><img height=36 width=36 alt="CONTENTS" src="/UCESIcons/tools/toc.gif"></a></td> </table> </center> <HR> <H3>Trig Values of -120°</H3> <P> Now let <IMG WIDTH=71 HEIGHT=22 ALIGN=MIDDLE ALT="theta=-120 degrees" SRC="img70.gif">. Note that this angle is determined in a clockwise fashion, starting at the positve <I>x</I>-axis, since it is a negative angle. We see in the diagram that the reference angle here is <IMG WIDTH=57 HEIGHT=12 ALIGN=BOTTOM ALT="theta* = 60 degrees" SRC="img71.gif"> and that we are working with a <nobr>30°- 60°- 90°</nobr> triangle positioned in Quadrant III. <P> <CENTER> <IMG SRC="p8-6.gif" ALT="[diagram]" WIDTH=213 HEIGHT=164> </CENTER> <P> From this we can see that we have: <P> <CENTER> <IMG WIDTH=296 HEIGHT=136 ALIGN=BOTTOM ALT="[trig values for -120 degrees]" SRC="img76.gif"> </CENTER> <P> <HR><center> <table border=1> <td><A HREF="node32.html"><img height=36 width=36 alt="PREVIOUS" src="/UCESIcons/tools/previous.gif"></A></td> <td><A HREF="node31.html"><img height=36 width=36 alt="UP" src="/UCESIcons/tools/up.gif"></A></td> <td><A HREF="node34.html"><img height=36 width=36 alt="NEXT" src="/UCESIcons/tools/next.gif"></A></td> <td><a href="contents-node33.html"><img height=36 width=36 alt="CONTENTS" src="/UCESIcons/tools/toc.gif"></a></td> </table> </center> <HR><P><ADDRESS> <I><A HREF="http://www.math.psu.edu/sellersj/">James A. Sellers</A> </I> </ADDRESS> </BODY>