document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=682514>Question 682514</A>: <I><SPAN STYLE=\"word-break: break-all;\"> solve the equation for x.\r<BR>\n" );
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document.write( "arctan x = arccos(5/13) </SPAN>\n" );
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document.write( "arctan x = arccos(5/13)<BR>\n" );
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document.write( "arccos(5/13) means an angle whose cos=5/13=adjacent side/hypotenuse<BR>\n" );
document.write( "opposite side=&#8730;(13^2-5^2)=&#8730;(169-25)=&#8730;144=12 (by Pythagorean Theorem)<BR>\n" );
document.write( "tan=opposite side/adjacent side=12/5<BR>\n" );
document.write( "arctan x=the same angle whose cos=5/13<BR>\n" );
document.write( "arctan(12/5) = arccos(5/13)<BR>\n" );
document.write( "x=12/5 </SPAN>\n" );
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