document.write( "Question 613143: What is cos(theta/2) when sin(theta) is 1/3 ? [90 < theta < 180] \n" ); document.write( "

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What is cos(theta/2) when sin(theta) is 1/3 ? [90 < theta < 180]
\n" ); document.write( "If sinx=1/3=oppposite side/hypotenuse
\n" ); document.write( "adjacent side=√(9-1)=√8
\n" ); document.write( "reference angle in quadrant II where sin>0 and cos<0
\n" ); document.write( "cosx=-√8/3
\n" ); document.write( "use half angle formula to solve for cos (x/2)
\n" ); document.write( "cos(x/2)=-√[(1+cosx)/2]
\n" ); document.write( "=-√[(1-√8/3)/2]
\n" ); document.write( "=-√[(3-√8)/6]
\n" ); document.write( " \n" ); document.write( "

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