Sin 15 / sin 5 - sin 75 / cos 5
Sin15/sin5 -sin75/cos5=sin15/sin5 -sin(90-15)/cos5=sin15/sin5 -cos15/cos5= =(sin15*cos5-cos15*sin5)/sin5cos5=sin(15-5)/0,5sin10=sin10/0,5sin10=2