document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=932116>Question 932116</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I have a Russian Trig teacher and could not understand this lesson. We were suppose to prove the identities.\r<BR>\n" );
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document.write( "The problem is:<BR>\n" );
document.write( "Prove cos(810degrees-x)=sinx\r<BR>\n" );
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document.write( "He was suppose to give us the formula for it, but never did. I think if you can just explain this first one I'll be able to figure out the rest.\r<BR>\n" );
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document.write( "Thanks! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #565968 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=565968\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Prove cos(810degrees-x)=sinx <BR>\n" );
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document.write( "You can always throw away multiples of 360 degrees.<BR>\n" );
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document.write( "Your problem::<BR>\n" );
document.write( "810-2*360 = 90 degrees<BR>\n" );
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document.write( "So, cos(810 - x) = cos(90-x) = sin(x) <BR>\n" );
document.write( "because cos and sin are complementary trig functions.<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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