document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=29986>Question 29986</A>: <I><SPAN STYLE=\"word-break: break-all;\"> What are exact values of sin 7pi/6, tan2pi/3, sec7pi/4, sin(-19pi/6), tan 5pi/6 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #16746 by </B><A HREF=/tutors/aboutme.mpl?userid=longjonsilver><B>longjonsilver(2297)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=longjonsilver><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/cgi-bin/show-face.mpl?user=longjonsilver><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=16746\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Either switch your calculator to radians and type in (7*pi)/6 and then find te sin of that. Etc\r<BR>\n" );
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document.write( "or convert the radians to degrees first and then find te sin etc.\r<BR>\n" );
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document.write( "I shall do the second method, since the first is just you using a calculator.\r<BR>\n" );
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document.write( "ALWAYS START WITH WHAT YOU KNOW: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2%2Api ALIGN=MIDDLE  ALT=\"2%2Api\"   DISABLED_style= \"max-width:90%; height:auto;\" > radians is 360 degrees\r<BR>\n" );
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document.write( "So, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=pi+=+180 ALIGN=MIDDLE  ALT=\"pi+=+180\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Hence <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%287%2Api%29%2F6+=+%287%2F6%29%2A180 ALIGN=MIDDLE  ALT=\"%287%2Api%29%2F6+=+%287%2F6%29%2A180\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "which is 210 degrees\r<BR>\n" );
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document.write( "So sin210 is? use your calculator here. Or, if you truly understand TRIG manipulation, do it by yourself: realise that 210 degrees is in the 3rd quadrant, where sin is always -ve. The equivalent 1st quadrant angle here would be 180+x = 210 --> x is 30. So sin30 is 1/2. \r<BR>\n" );
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document.write( "Answer is -(1/2)...check on your calculator that this is correct :-)\r<BR>\n" );
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document.write( "You do the rest :-)\r<BR>\n" );
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document.write( "jon.<BR>\n" );
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