document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=942396>Question 942396</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If cosine is 2/5, find sin and tan.\r<BR>\n" );
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document.write( "Any help on how to do this? Thanks! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #574520 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=574520\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> cosine is equal to 2/5<BR>\n" );
document.write( "cosine is positive in quadrants 1 and 4.<BR>\n" );
document.write( "since cosine is equal to adjacent / hypotenuse, then you can solve for opposite using pythagorus formula of a^2 + b^2 = c^2.<BR>\n" );
document.write( "let a = 2 and c = 5<BR>\n" );
document.write( "formula of a^2 + b^2 = c^2 becomes 2^2 + b^2 = 5^2.<BR>\n" );
document.write( "solve for b^2 to get b^2 = 5^2 - 2^2 = 25 - 4 = 21.<BR>\n" );
document.write( "this makes b = plus or minus sqrt(21)<BR>\n" );
document.write( "a is the side adjacent which is 2.<BR>\n" );
document.write( "b is the side opposite which is plus or minus sqrt(21).<BR>\n" );
document.write( "c is the hypotenuse which is 5.<BR>\n" );
document.write( "in quadrant 1, side opposite is positive so side opposite is equal to sqrt(21).<BR>\n" );
document.write( "in quadrant 4, side opposite is negative so side opposite is equal to -sqrt(21).<BR>\n" );
document.write( "hypotenuse of 5 is always positive.<BR>\n" );
document.write( "side adjacent is always equal to 2 in both quadrants 1 and 4.<BR>\n" );
document.write( "sine is equal to side opposite divided by hypotenuse.<BR>\n" );
document.write( "this makes sine equal to sqrt(21)/5 in quadrant 1 and -sqrt(21)/5 in quadrant 4.<BR>\n" );
document.write( "tangent is equal to side opposite divided by side adjacent.<BR>\n" );
document.write( "this makes tangent equal to sqrt(21)/2 in quadrant 1 and -sqrt(21)/2 in quadrant 4.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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