document.write( "Question 976153: Verify that
\n" ); document.write( "(1-tanx)/(1+tanx)= 2cos^2x-1 \n" ); document.write( "
Algebra.Com's Answer #597815 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
There must be a typo, but I cannot guess what it should be.
\n" ); document.write( "\"%281-tan%28x%29%29%2F%281%2Btan%28x%29%29=2cos%5E2%28x%29-1\" is not true for all values of \"x\" .
\n" ); document.write( "For example, for the angle shown here ,
\n" ); document.write( "\"cos%28red%28x%29%29=4%2F5=0.8\" , \"sin%28red%28x%29%29=3%2F5=0.6%29\" , and \"tan%28red%28x%29%29=3%2F4=0.75\" .
\n" ); document.write( "In that case,
\n" ); document.write( " (rounded), and
\n" ); document.write( "\"2cos%5E2%28red%28x%29%29-1=2%2A0.8%5E2-1=2%2A0.64-1=1.28-1=0.28\"
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