document.write( "Question 724700: Write the expression as the sine, cosine, and tangent of an angle: \r
\n" ); document.write( "\n" ); document.write( "Sin 330 cos 45 - cos 330 sin 45 \n" ); document.write( "
Algebra.Com's Answer #443867 by lwsshak3(11628)\"\" \"About 
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Write the expression as the sine, cosine, and tangent of an angle:
\n" ); document.write( "Sin 330 cos 45 - cos 330 sin 45
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\n" ); document.write( "Use sin addition formula: sin(s-t)=sin s cos t-cos s sin t
\n" ); document.write( "Sin 330 cos 45 - cos 330 sin 45=sin(330-45)=sin(285)
\n" ); document.write( "reference angle=360-285=75º(in quadrant IV where sin<0), cos>0, tan<0
\n" ); document.write( "sin75º=sin(30+45)
\n" ); document.write( "=sin 30 cos 45-cos 30 sin 45
\n" ); document.write( "=1/2*√2/2-√3/2*√2/2
\n" ); document.write( "=√2/4-√6/4
\n" ); document.write( "=(√2-√6)/4
\n" ); document.write( "sin 75=-(√2-√6)/4
\n" ); document.write( "...
\n" ); document.write( "cos75º=cos(30+45)
\n" ); document.write( "=cos 30 cos 45-sin 30 sin 45
\n" ); document.write( "=√3/2*√2/2-1/2*√2/2
\n" ); document.write( "=√6/4-√2/4
\n" ); document.write( "=(√6-√2)/4
\n" ); document.write( "cos 75º=(√6-√2)/4
\n" ); document.write( "..
\n" ); document.write( "tan75º=tan(30+45)
\n" ); document.write( "=(tan 30+tan 45)/tan 30*tan 45
\n" ); document.write( "=(√3/3+1)/√3/3*1
\n" ); document.write( "=(√3/3+1)/√3/3
\n" ); document.write( "tan75º=-(√3/3+1)/√3/3 \n" ); document.write( "
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