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21 Contoh Soal Limit Trigonometri Kelas 12 beserta Jawabannya untuk Bahan Belajar

Kalau kamu sudah paham bagaimana menerapkan rumus, maka materi limit trigonometri akan terasa lebih mudah. Yuk, Mamikos temani kamu belajar menggunakan contoh soal di artikel berikut ini!

1 Oktober 2025 Lintang Filia

Contoh Soal Limit Trigonometri Kelas 12 beserta Jawabannya Bagian 2

11. Hitung nilai limit berikut \[ \lim_{x \to 0} \frac{\tan(3x) - \sin(3x)}{x^3} \]

Pembahasan:

Gunakan ekspansi limit kecil \[ \tan u \approx u + \frac{u^3}{3}, \qquad \sin u \approx u - \frac{u^3}{6} \]

\[ \tan(3x) - \sin(3x) \approx \left(3x + \frac{(3x)^3}{3}\right) - \left(3x - \frac{(3x)^3}{6}\right)

= 9x^3 + \frac{27}{6} x^3

= \frac{27}{2} x^3 \]

\[ \lim_{x \to 0} \frac{\tan(3x) - \sin(3x)}{x^3} = \lim_{x \to 0} \frac{\frac{27}{2} x^3}{x^3} = \frac{27}{2} \]

Jawaban: \[ \frac{27}{2} \]

12. Tentukan hasil limit \[ \lim_{x \to \frac{\pi}{4}} \frac{1 - \tan x}{\sin x - \cos x} \]

Pembahasan:

\lim_{x \to \frac{\pi}{4}} \frac{1 - \tan x}{\sin x - \cos x}

= \lim_{x \to \frac{\pi}{4}} \frac{1 - \frac{\sin x}{\cos x}}{\sin x - \cos x}

= \lim_{x \to \frac{\pi}{4}} \frac{\frac{\cos x - \sin x}{\cos x}}{\sin x - \cos x}

= \lim_{x \to \frac{\pi}{4}} \frac{-(\sin x - \cos x)}{\cos x (\sin x - \cos x)}

= \lim_{x \to \frac{\pi}{4}} \frac{-1}{\cos x}

= -\frac{1}{\frac{\sqrt{2}}{2}}

= -\sqrt{2}

Jawaban: \[ -\sqrt{2} \]

13. Nilai dari \[ \lim_{x \to 0} \frac{\sin(4x)}{\tan(7x)} \]

Pembahasan:

\[ \lim_{x \to 0} \frac{\sin(4x)}{\tan(7x)}

= \lim_{x \to 0} \frac{\sin(4x)}{\frac{\sin(7x)}{\cos(7x)}}

= \lim_{x \to 0} \frac{\sin(4x) \cos(7x)}{\sin(7x)}

= \frac{4}{7} \cdot 1

= \frac{4}{7} \]

Jawaban: \[ \frac{4}{7} \]

13. Tentukan hasil limit berikut \[ \lim_{x \to \frac{\pi}{3}} \frac{\cos x - \frac{1}{2}}{x - \frac{\pi}{3}} \]

Pembahasan:

Bentuk turunan definisi.

\[ -\sin\left(\frac{\pi}{3}\right) = -\frac{\sqrt{3}}{2} \]

Jawaban: \[ -\frac{\sqrt{3}}{2} \]

14. Hitung nilai limit \[ \lim_{x \to 0} \frac{\sin(5x) - \tan(5x)}{x^3} \]

Pembahasan:

Gunakan pendekatan deret:

\[ \sin(5x) - \tan(5x) \approx \left(5x - \frac{(5x)^3}{6}\right) - \left(5x + \frac{(5x)^3}{3}\right) \]

= -\frac{125}{6} x^3 - \frac{125}{3} x^3

= -\frac{125}{2} x^3

\[ \lim_{x \to 0} \frac{\sin(5x) - \tan(5x)}{x^3} = \lim_{x \to 0} \frac{-\frac{125}{2} x^3}{x^3} = -\frac{125}{2} \]

Jawaban: \[ -\frac{125}{2} \]

15. Tentukan nilai dari \[ \lim_{x \to \frac{\pi}{4}} \frac{\tan(2x) - 1}{x - \frac{\pi}{4}} \]

Pembahasan:

Turunan dari \tan(2x) \text{ di titik } x = \frac{\pi}{4}

\[ \frac{d}{dx} \big(\tan(2x)\big) = 2 \sec^2(2x) \]

Substitusi x = \frac{\pi}{4}:

\[ 2 \sec^2\left(\frac{\pi}{2}\right) \to 2 \cdot \infty \]

Limit tidak terdefinisi (menuju tak hingga).

Jawaban: ∞

16. Nilai dari \[ \lim_{x \to 0} \frac{\sin(3x) \cos(2x)}{x} \]

Pembahasan:

\[ \lim_{x \to 0} \frac{\sin(3x) \cos(2x)}{x}

= \lim_{x \to 0} \frac{\sin(3x)}{x} \cdot \cos(2x)

= 3 \cdot 1

= 3 \]

Jawaban: 3

17. Nilai dari \[ \lim_{x \to 0} \frac{\tan(2x) - \sin(2x)}{x^3} \]

Pembahasan:

Gunakan pendekatan deret:

\[ \tan(2x) - \sin(2x) \approx \left(2x + \frac{(2x)^3}{3}\right) - \left(2x - \frac{(2x)^3}{6}\right)

= \frac{8}{3}x^3 + \frac{4}{3}x^3

= 4x^3

\[ \lim_{x \to 0} \frac{\tan(2x) - \sin(2x)}{x^3} = \lim_{x \to 0} \frac{4x^3}{x^3} = 4 \]

Jawaban: 4

18. Hitung limit berikut \[ \lim_{x \to \frac{\pi}{2}} \frac{1 - \sin x}{\cos^2 x} \]

Pembahasan:

Gunakan identitas: \[ 1 - \sin x = \frac{(1 - \sin x)(1 + \sin x)}{1 + \sin x} \]

\[ \lim_{x \to \frac{\pi}{2}} \frac{1 - \sin x}{\cos^2 x}

= \lim_{x \to \frac{\pi}{2}} \frac{1 - \sin^2 x}{(1 + \sin x)\cos^2 x}

= \lim_{x \to \frac{\pi}{2}} \frac{\cos^2 x}{(1 + \sin x)\cos^2 x}

= \frac{1}{1 + \sin\left(\frac{\pi}{2}\right)}

= \frac{1}{2} \]

Jawaban: \[ \frac{1}{2} \]

19. Nilai dari \[ \lim_{x \to 0} \frac{\sin(7x)}{\tan(4x)} \]

Pembahasan:

\lim_{x \to 0} \frac{\sin(7x)}{\tan(4x)}

= \lim_{x \to 0} \frac{\sin(7x)}{\frac{\sin(4x)}{\cos(4x)}}

= \lim_{x \to 0} \frac{\sin(7x)\cos(4x)}{\sin(4x)}

= \frac{7}{4} \cdot 1

= \frac{7}{4} \]

Jawaban: \[ \frac{7}{4} \]

Halaman:

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