document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=241747>Question 241747</A>: <I><SPAN STYLE=\"word-break: break-all;\"> what is the value of the expression cos-1 (&#8730;2\2) ? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #177056 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=177056\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> From the unit circle, we see that <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \cos\left(\frac{\pi}{4}\right)=\frac{\sqrt{2}}{2}\">. \r<BR>\n" );
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document.write( "So applying the inverse cosine to both sides gets us: <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \cos^{-1}\left(\cos\left(\frac{\pi}{4}\right)\right)=\cos^{-1}\left(\frac{\sqrt{2}}{2}\right)\">. \r<BR>\n" );
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document.write( "which simplifies to <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \frac{\pi}{4}=\cos^{-1}\left(\frac{\sqrt{2}}{2}\right)\">.\r<BR>\n" );
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document.write( "So <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \cos^{-1}\left(\frac{\sqrt{2}}{2}\right)=\frac{\pi}{4}\"> where we're restricting the angle to be between 0 and <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \pi\"> </SPAN>\n" );
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