Выражение: cos(a+32°)+cos(a-28°)/sin(88°-a)

cos(a+32°)+cos(a-28°)/sin(88°-a)=

=[2cos((a+32+a-28)/2)*cos((a+32-a+28)/2)]/sin(88-a)=

=[2cos((2a+4)/2)*cos60/2]/sin(88-a)=

=[2cos(a+2)*cos30]/sin(88-a)=

=[2cos(a+2)*sqrt{3}/2]/sin(88-a)=

=[sqrt{3}cos(a+2)]/sin(90-2-a)=

=[sqrt{3}cos(a+2)]/cos(-(2+a))=

{sqrt{3}cos(a+2)]/cos(2+a)=

=sqrt{3}