document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1203785>Question 1203785</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I'm so confused on what my math teacher is asking...<BR>\n" );
document.write( "Sin θ=4/5, cos θ=-3/5<BR>\n" );
document.write( "I need to find θ but I don't understand how to solve for it. If you could show me how to do it or maybe even if possible show me some examples it would be greatly appreciated because I really want to try and solve the rest of the problems myself. :D </SPAN>\n" );
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document.write( "sin(θ) = 4/5<BR>\n" );
document.write( "θ = arcsin(4/5) or θ = 180 - arcsin(4/5)<BR>\n" );
document.write( "θ = 53.1301° or θ = 126.8699°<BR>\n" );
document.write( "Both are approximate.\r<BR>\n" );
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document.write( "Arcsine refers to inverse sine, denoted on many calculators as the button <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\large \sin^{-1}\"><BR>\n" );
document.write( "Take note how sin(53.1301°) = 4/5 = 0.8 approximately and also sin(126.8699°) = 4/5 = 0.8 approximately as well.\r<BR>\n" );
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document.write( "The answer we want is either θ = 53.1301° or θ = 126.8699°\r<BR>\n" );
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document.write( "Which one do we pick? We go for the one that makes cosine negative.<BR>\n" );
document.write( "cos(53.1301°) = 0.6 = 3/5<BR>\n" );
document.write( "cos(126.8699°) = -0.6 = -3/5\r<BR>\n" );
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document.write( "Therefore, <font color=red>θ = 126.8699° approximately</font>\r<BR>\n" );
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document.write( "To convert to radians, multiply by the conversion factor pi/180.<BR>\n" );
document.write( "This would mean:<BR>\n" );
document.write( "126.8699° = 126.8699*(pi/180) = 2.2143 radians approximately<BR>\n" );
document.write( "In my opinion, degrees are easier to work with in this context.\r<BR>\n" );
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document.write( "Side note: The angle 126.8699° is in quadrant 2, aka the northwest quadrant.<BR>\n" );
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