Question

sin5cos15+cos5sin15/cos80cos150+sin80sin150

Answer 1

sin5cos15+cos5sin15/cos80cos150+sin80sin150 =sin(5+15)/cos(150-80) =
sin20/cos70 = sin(30-10)/cos(60+10) = 1/2cos10 -$frac{ sqrt{3} }{2}$sin10/$frac{ sqrt{2} }{2}$cos10 - $frac{ sqrt{2} }{2}$sin10 = 

Answer 2

не очень но все же...))