document.write( "Question 84895: Determine the exact value of the trigonometric functions listed below.\r
\n" ); document.write( "\n" ); document.write( "cot (135) = is it -1?\r
\n" ); document.write( "\n" ); document.write( "cos(pi/12)....where do I start?
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Algebra.Com's Answer #61178 by jim_thompson5910(35256)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "So you are correct \"cot+%28135%29=-1\"\r
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\n" ); document.write( "\n" ); document.write( "\"cos%28pi%2F12%29=cos%28pi%2F3-pi%2F4%29\" Break up the argument. Note: \"pi%2F3-pi%2F4=4pi%2F12-3pi%2F12=1pi%2F12=pi%2F12\"\r
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\n" ); document.write( "\n" ); document.write( "Now use the trig identity:\r
\n" ); document.write( "\n" ); document.write( "\"cos%28A-B%29=cos%28A%29cos%28B%29%2Bsin%28A%29sin%28B%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"cos%28pi%2F3-pi%2F4%29=cos%28pi%2F3%29cos%28pi%2F4%29%2Bsin%28pi%2F3%29sin%28pi%2F4%29\" Plug in \"A=pi%2F3\" and \"B=pi%2F4\"\r
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\n" ); document.write( "\n" ); document.write( "Now using the unit circle, we get \"cos%28pi%2F3%29=1%2F2\", \"cos%28pi%2F4%29=sqrt%282%29%2F2\", \"sin%28pi%2F3%29=sqrt%283%29%2F2\", and \"sin%28pi%2F3%29=sqrt%282%29%2F2\"\r
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\n" ); document.write( "\n" ); document.write( " Substitute each trig function with it's corresponding expression\r
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\n" ); document.write( "\n" ); document.write( "\"cos%28pi%2F3-pi%2F4%29=sqrt%282%29%2F4%2Bsqrt%286%29%2F4\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"cos%28pi%2F3-pi%2F4%29=%28sqrt%282%29%2Bsqrt%286%29%29%2F4\" Combine the fractions\r
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\n" ); document.write( "\n" ); document.write( "So \r
\n" ); document.write( "\n" ); document.write( "\"cos%28pi%2F12%29=%28sqrt%282%29%2Bsqrt%286%29%29%2F4\"\r
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