document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=717656>Question 717656</A>: <I><SPAN STYLE=\"word-break: break-all;\"> what is cos alpha when sin is 4/5 and tan is less than zero </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #440374 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=440374\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> what is cos alpha when sin is 4/5 and tan is less than zero<BR>\n" );
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document.write( "If sin is 4/5 the angle is in QI or in QII<BR>\n" );
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document.write( "If tan is less than zero, the angle must be in QII where x is neg and y is pos:<BR>\n" );
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document.write( "If sin = y/r = 4/5, y = 4 and r = 5<BR>\n" );
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document.write( "Then x = -sqrt(5^2-4^2) = -sqrt(9) = -3<BR>\n" );
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document.write( "So: <BR>\n" );
document.write( "r = 5<BR>\n" );
document.write( "x = -3<BR>\n" );
document.write( "y = 4<BR>\n" );
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document.write( "Ans: cos(theta) = x/r = -3/5<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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