Matematika Peminatan Sukino Kelas XII
Bab 2 Turunan Fungsi Trigonometri
LKS 4
Soal dan Pembahasan Matematika Sukino Peminatan
Bagian A
10. Diketahui h (θ) = (2 + cos θ) / sin θ . Nilai dari h ' (π/3) = ...
a. -8/3
b. -4/3
c. 3/8
d. 3/4
e. 8/3
Jawaban : A
h (θ) = (2 + cos θ) / sin θ
u = 2 + cos θ
u ' = - sin θ
v = sin θ
v ' = cos θ
- sin θ . (sin θ) - (cos θ) . (2 + cos θ)
h ' (θ) = --------------------------------------------
(sin θ)2
- sin2 θ - (2 cos θ + cos2 θ)
h ' (θ) = ----------------------------------
(sin θ)2
- sin2 θ - 2 cos θ - cos2 θ
h ' (θ) = --------------------------------
(sin θ)2
- (sin2 θ + cos2 θ) - 2 cos θ
h ' (θ) = --------------------------------
(sin θ)2
sifat : sin2 θ + cos2 θ = 1
- 1 - 2 cos θ
h ' (θ) = ----------------
(sin θ)2
- 1 - 2 cos π/3
h ' (π/3) = ----------------
(sin π/3)2
- 1 - 2 . 1/2
h ' (π/3) = ----------------
(1/2 √3 )2
- 1 - 1
h ' (π/3) = -------
3/4
h ' (π/3) = - 2 . 4/3
h ' (π/3) = -8/3
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