document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=825698>Question 825698</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If sec&#952;= 4/5 and &#952; terminates in Quadrant II, find the exact value of sin2&#952;.<BR>\n" );
document.write( "F. -24/25<BR>\n" );
document.write( "G. 8/5 (I chose this one and it was wrong)<BR>\n" );
document.write( "H.-12/25<BR>\n" );
document.write( "J. 24/25 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #497514 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=497514\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I'm going to use x in place of &#952; (it's easier to type)\r<BR>\n" );
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document.write( "sec(x) = 4/5\r<BR>\n" );
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document.write( "1/cos(x) = 4/5\r<BR>\n" );
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document.write( "cos(x) = 5/4 ... take the reciprocal of both sides\r<BR>\n" );
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document.write( "cos^2(x) = 25/16 ... square both sides\r<BR>\n" );
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document.write( "sin^2(x) + cos^2(x) = 1\r<BR>\n" );
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document.write( "sin^2(x) + 25/16 = 1\r<BR>\n" );
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document.write( "sin^2(x) = 1 - 25/16\r<BR>\n" );
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document.write( "sin^2(x) = 16/16 - 25/16\r<BR>\n" );
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document.write( "sin^2(x) = (16 - 25)/16\r<BR>\n" );
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document.write( "sin^2(x) = -9/16\r<BR>\n" );
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document.write( "sin(x) = sqrt(-9/16)\r<BR>\n" );
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document.write( "As you can see in the last step above, we have sqrt(-9/16), but we cannot take the square root of a negative number and get a real number as a result. So this leads me to think that there's a typo somewhere. Please double check. Thanks. </SPAN>\n" );
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