Nilai Limit x mendekati π/4 cos2x/cosx – sinx

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Jawab:

Nilai    Lim          cos 2x
          x ➝ π/4   cosx – sinx
= Lim        cos²x – sin²x
   x ➝ π/4  cos x – sin x
= Lim         (cosx + sinx)(cosx – sinx)
   x ➝ π/4             (cosx – sinx)
= cos π/4 + sin π/4
= 1/2 √2 + 1/2 √2
= √2
  Identitas Trigonometri: Persamaan, Grafik Fungsi, Tabel, Sudut Istimewa, Contoh Soal