document.write( "Question 594805: Use a half-way identity to find exact value for sin(theta),cos(theta), and tan(theta), theta= 75 degrees. \n" ); document.write( "
Algebra.Com's Answer #376933 by lwsshak3(11628)\"\" \"About 
You can put this solution on YOUR website!
Use a half-way identity to find exact value for sin(theta),cos(theta), and tan(theta), theta= 75 degrees.
\n" ); document.write( "**
\n" ); document.write( "Half-Angle Formulas:
\n" ); document.write( "sin x/2=±√[(1-cos x)/2)]
\n" ); document.write( "cos x/2=±√[(1+cos x)/2)]
\n" ); document.write( "tan x/2=(sin x)/(1+cos x)
\n" ); document.write( "..
\n" ); document.write( "sin 75º=sin 150/2=±√[(1-cos 150)/2)] (use positive root because 75º is in quadrant I where sin>0)
\n" ); document.write( "=√[(1-(-√3/2))/2)]
\n" ); document.write( "=√[(1+√3/2)/2)]
\n" ); document.write( "=√.933≈.966
\n" ); document.write( "..
\n" ); document.write( "cos 75º=cos 150/2=±√[(1+cos 150)/2)] (use positive root because 75º is in quadrant I where cos>0)
\n" ); document.write( "=√[(1+(-√3/2))/2)]
\n" ); document.write( "=√[(1-√3/2)/2)]
\n" ); document.write( "=√.067≈.259
\n" ); document.write( "..
\n" ); document.write( "tan 75º=tan 150/2=sin 150/(1+cos 150)
\n" ); document.write( "=(1/2)/(1+(-√3/2))
\n" ); document.write( "≈3.73 \n" ); document.write( "
\n" );