2. Nilai dari sin (4π/6) + sin (-5π/6) adalah…
3. Nilai dari cos (7π/6) + sin (-5π/3) adalah…
4. Diketahui f(∅) = tan ∅ + 2. Nilai dari f (0) + f (7π/4) – 3 adalah…
1. Nilai dari cos (30) + cos (-30) adalah…
Jawab:
Penjelasan dengan langkah-langkah:
1.
cos 30˚ + cos (-30˚)
= cos 30˚ + cos (30˚)
= 2 cos 30˚
= 2 * (1/2)√3
= √3
2.
sin (4π/6) + sin (-5π/6)
= sin 120˚ + (- sin 150˚)
= sin 120˚ – sin 150˚
= sin 60˚ – sin 30˚
= (1/2)√3 – (1/2)
= (1/2) (√3 – 1)
3.
cos (7π/6) + sin (- 5π/3)
= cos 210˚ – sin 300˚
= -(1/2)√3 – (1/2)√3
= -√3
4.
f(ø) = tan ø + 2
f(0˚) + f(7π/4) – 3
= 2 + tan 315˚ + 2 – 3
= 1 + tan 315˚
= 1 + (-1)
= 0