Jawabanmu

  • Pengguna Brainly
2014-03-25T06:59:26+07:00
=sin 30 (1 -2sin²30)-(2.sin30.cos30) cos30
=sin30 - 2sin³30 - 2sin30.cos²30
=sin30 -2sin30(sin²30+cos²30)
=sin30-2sin30.1
= -sin30
=- \frac{1}{2}
2014-03-25T07:01:05+07:00
Sin 30 x cos 60 - sin 60 x cos 30
= 1/2 x 1/2 - 1/2√3 x 1/2√3
= 1/4 - 3/4
= -2/4

cos 30 x cos 60 +sin 30 x sin 60
= 1/2√3 x 1/2 + 1/2 x 1/2√3
= √3/4 + √3/4
2√3/4