Cos 150 + sin 120 + tan 300 + Cotan 60=

cos 150 = cos (180-30) = - cos 30 = - 1/2 akar 3
sin 120 = sin 90 + 30 = sin 30 = 1/2
tan 300 = tan (360-60) = - tan 60 = -1/2 akar 2
cotan 60 = 1/tan 60 = 1/1/2 akar 2 = akar 2
-akar 3/2 + 1/2 + -akar 2/2 + 2akar 2 /2
= (-akar 3+1+ akar 2)/2

mohon maaf apabila ada kesalahan