document.write( "Question 800722: Prove that tan(10°)cos(20°)tan(40°)tan(50°)csc(70°)sec(80°)sin(80°) = 1 \n" ); document.write( "

Algebra.Com's Answer #483243 by Edwin McCravy(20056) $\"\"$ $\"About$

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document.write( "Prove that tan(10°)cos(20°)tan(40°)tan(50°)csc(70°)sec(80°)sin(80°) = 1\r\n" );
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document.write( "Change all trig ratios other than the sines and cosines\r\n" );
document.write( "to sines and cosines, and put 1 denominators under the \r\n" );
document.write( "sines and cosines, using these quotient and reciprocal \r\n" );
document.write( "identities: \r\n" );
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document.write( ", , \r\n" );
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document.write( "Next change all the cosines to sines using the cofuction identity:\r\n" );
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document.write( "Substitute those for all the cosines:\r\n" );
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document.write( "That all cancels and gives 1\r\n" );
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document.write( "Edwin

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