arra
tan 660 derajat - sin 990derajat+cos (-390)derajat = -akar3 - (-1) + (akar3/2) = -akar3 +1+(akar3/2) = 1-(akar3/2) ,, ddiket: tan 660=-akar3, sin 990=-1, cos (-390)=(akar3/2)
danyriansyahputra
Tan 660-sin 900+ cos (-390)=tan 60 - sin 80 + (cos -30) =akar 3 - sin 80 + (-1/2 akar 3) =5/2 akar 3 - sin 80
=akar 3 - sin 80 + (-1/2 akar 3)
=5/2 akar 3 - sin 80