buktikan identitas trigonometri berikut!
Sin x / Cos x - Cos x / Sin x = Cos2x / Sinx Cosx
Sin x / Cos x - Cos x / Sin x = Cos2x / Sinx Cosx
Jawab:
(sin x / cos x) – (cos x / sin x) = – [cos 2x / (sin x cos x)] terbukti.
Penjelasan dengan langkah-langkah:
Pembuktian Identitas Trigonometri
Ruas kiri
= (sin x / cos x) – (cos x / sin x)
- samakan penyebut
= [(sin x sin x) / (sin x cos x)] – [(cos x cos x) / (sin x cos x) ]
= (sin² x – cos² x) / (sin x cos x)
- sin² x – cos² x = –(cos² x – sin² x)
→ sin² x – cos² x = –cos 2x
= –cos 2x / (sin x cos x)
= – [cos 2x / (sin x cos x)]
= Ruas kanan.
⇒ terbukti!
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