document.write( "Question 761565: Use an Addition or Subtraction Formula to find the exact value of the expression, as demonstrated in Example 1.
\n" ); document.write( "1. tan(-11pi/12)
\n" ); document.write( "2. sin(-11pi/12)\r
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Algebra.Com's Answer #463304 by lwsshak3(11628)\"\" \"About 
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Use an Addition or Subtraction Formula to find the exact value of the expression, as demonstrated in Example 1.
\n" ); document.write( "1. tan(-11pi/12)=tan(13π/12)=tan(9π/12+4π/12)=tan(3π/4+π/3)=-1+√3)/1-tan(3π/4)*tan(π/3)
\n" ); document.write( "=(-1+√3)/(1-(-1*√3)=-(1-√3)/(1+√3)*(1+√3)/(1+√3)=(1-2√3+3)/(1-3)=(4-2√3)/2=2-√3
\n" ); document.write( "calculator check:
\n" ); document.write( "tan(-11π/12≈0.2679
\n" ); document.write( "exact value=2-√3≈.2679
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\n" ); document.write( "2. sin(-11pi/12)=sin(13π/12)=sin(9π/12+4π/12)=sin(3π/4+π/3)=√2/2*1/2+(-√2/2*√3/2
\n" ); document.write( "=√2/4-√6/4=(√2-√6)/4
\n" ); document.write( "Calculator check:
\n" ); document.write( "sin(-11π/12)≈-0.2588
\n" ); document.write( "Exact value=(√2-√6)/4≈0.2588 \n" ); document.write( "
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