document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=767420>Question 767420</A>: <I><SPAN STYLE=\"word-break: break-all;\"> find the exact value using a double angle identity\r<BR>\n" );
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document.write( "cos(450) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #467712 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><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=467712\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> find the exact value using a double angle identity <BR>\n" );
document.write( "cos(450)<BR>\n" );
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document.write( "cos2x=cos^2x-sin^2x\r<BR>\n" );
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document.write( "cos(450)=cos(2*225)=cos^2(225º)-sin^2(225º)<BR>\n" );
document.write( "cos(225º)=-&#8730;2/2 in Q3<BR>\n" );
document.write( "cos^2(225º)=2/4=1/2<BR>\n" );
document.write( "sin(225º)=-&#8730;2/2 in Q3<BR>\n" );
document.write( "sin^2(225º)=2/4=1/2<BR>\n" );
document.write( "cos(450)=cos(2*225)=cos^2(225º)-sin^2(225º)=1/2-12=0<BR>\n" );
document.write( "calculator check:<BR>\n" );
document.write( "cos 450º=0 </SPAN>\n" );
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