Question

cos 64°cos4°-sin4°sin 64°/cos 71°cos41°+sin41°sin71°

Answer 1

$frac{cos64*cos4+sin4*sin64}{cos71*cos41+sin41sin71}= frac{cos(64-4)}{cos(71-41)}= frac{cos60}{cos30}= frac{1}{2}* frac{2}{ sqrt{3}}= frac{1}{ sqrt{3}}$