document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=929156>Question 929156</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The question said find the exact value of each of the following under the given conditions \r<BR>\n" );
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document.write( "Sin a = 3/5,0 < a < pi/2; cos b= 4 radical97/97,-pi/2<b<0\r<BR>\n" );
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document.write( "1.sin (a+b)<BR>\n" );
document.write( "2 cos(a+b)<BR>\n" );
document.write( "3 sin (a-b)<BR>\n" );
document.write( "4 cos(a-b) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #564141 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=564141\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> find the exact value of each of the following under the given conditions \r<BR>\n" );
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document.write( "Sin a = 3/5,0 < a < pi/2; <BR>\n" );
document.write( "cos b= 4 radical97/97,-pi/2 < b < 0\r<BR>\n" );
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document.write( "1.sin (a+b)<BR>\n" );
document.write( "sin(A+B) = sin(A)cos(B) + sin(B)cos(A)<BR>\n" );
document.write( "sin(A) = 3/5<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%28A%29+=+sqrt%281+-+sin%5E2%28A%29%29+=+sqrt%281+-+9%2F25%29+=+4%2F5 ALIGN=MIDDLE  ALT=\"cos%28A%29+=+sqrt%281+-+sin%5E2%28A%29%29+=+sqrt%281+-+9%2F25%29+=+4%2F5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "cos(A) is positive = 4/5<BR>\n" );
document.write( "---<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%28B%29+=+4sqrt%2897%29%2F97 ALIGN=MIDDLE  ALT=\"cos%28B%29+=+4sqrt%2897%29%2F97\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin%28B%29+=+sqrt%281+-+cos%5E2%28B%29%29+=+sqrt%281+-+16%2A97%29+=+sqrt%2881%2F97%29+=+9sqrt%2897%29%2F97 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "sub in Q4 is negative<BR>\n" );
document.write( "sin(B) = -9sqrt(97)/97<BR>\n" );
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document.write( "sin(A+B) = sin(A)cos(B) + sin(B)cos(A)<BR>\n" );
document.write( "= (3/5)*4sqrt(97)/97 - (9*sqrt(97)/97)*(4/5)<BR>\n" );
document.write( "= 12sqrt(97)/(97*5) - 36sqrt(97)/97)/(97*5)<BR>\n" );
document.write( "= -24sqrt(97)/485<BR>\n" );
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document.write( "These problems are tedious and it's easy to make a mistake.<BR>\n" );
document.write( "I'll check this tomorrow.<BR>\n" );
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document.write( "All these are similar.<BR>\n" );
document.write( "Look at \"half angle formulas\" on Wikipedia, it's covered well there.<BR>\n" );
document.write( "Try them and email me via the TY note for help, or to check your work.<BR>\n" );
document.write( "=====<BR>\n" );
document.write( "2 cos(a+b)<BR>\n" );
document.write( "3 sin (a-b)<BR>\n" );
document.write( "4 cos(a-b)<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );