document.write( "Question 1075809: cos^2 π/8 + cos^2 3π/8 +cos^2 5π/8 + cos^2 7π/8 \n" ); document.write( "
Algebra.Com's Answer #690452 by ikleyn(52799)\"\" \"About 
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document.write( "1.   \"cos%28pi%2F8%29\"  = \"-cos%287pi%2F8%29\".    Obviously.\r\n" );
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document.write( "     \"cos%283pi%2F8%29\" = \"-cos%285pi%2F8%29\".    Obviously.\r\n" );
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document.write( "2.   \"cos%28pi%2F8%29\" = \"sqrt%282%2Bsqrt%282%29%29%2F2\".\r\n" );
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document.write( "     See the lesson  Trigonometric functions of half argument - Examples  in this site.\r\n" );
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document.write( "3.   \"cos%283pi%2F8%29\" = \"sin%28pi%2F8%29\"    ( Obviouly )\r\n" );
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document.write( "                        = \"sqrt%282-sqrt%282%29%29%2F2\"\r\n" );
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document.write( "     See the lesson  Trigonometric functions of half argument - Examples  in this site.\r\n" );
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document.write( "4.   Now you are armed / prepared to complete this assignment on your own.\r\n" );
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