Question

1-2sin²43°/sin176°+sin4°

Answer 1

1-2sin²43°/sin176°+sin4°

$frac{1 - 2sin^243^0}{sin176^0+sin4^0}= \ \ frac{sin^243^0+cos^243^0 - 2sin^243^0}{2sin( frac{176^0+4^0}{2} )cos( frac{176^0-4^0}{2} )} = \ \ frac{cos^243^0 - sin^243^0}{2sin90^0cos86^0} = frac{cos86^0}{2cos86^0} =frac{1}{2} = 0,5$