Nilai sin 105+ cos 75=..

Cos 75 = cos (90-15) = cos 15

ingat!
sin a + sin b = 2 sin 1/2(a+b) cos 1/2(a-b)

so,
sin 105+sin 15 = 2 sin 1/2(105+15) cos 1/2 (105-15)
= 2 sin 60 cos 45
= 2.1/2√3.1/2√2
= 1/2√6

kasih jawaban terbaik ya hehehe