2 tentukan nilai daria) 12 Sin 105°b) 6-12 Sin² 67.5°cos 105°​

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2 tentukan nilai daria) 12 Sin 105°b) 6-12 Sin² 67.5°cos 105°​

TriGonmetRi

Nilai FUngsi

–

a) 12 Sin 105°

= 12 sin (60 + 45)

= 12 [ sin 60 cos 45 + cos 60 sin 45  ]

= 12 [ 1/2 √3  . 1/2 √2 + 1/2 . 1/2 √2]

= 12  [ 1/4 √6 + 1/4 √2]

= 12 . 1/4 [ √6 + √2 ]

= 3 ( √6 +  √2)

b) {6-12 Sin² 67.5°}  cos 105°​

=  6 ( 1 – 2 sin² 67,5) cos  105

= 6 ( cos 2(67,5) ) cos 105

= 6 cos 135  cos 105

= 3 (2 cos 135 cos 105)

= 3 { cos 240 + cos 30}

=  3 ( – 1/2 +  1/2 √3)

=  -3/2 ( 1  - √3)