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Kelas 10Kelas 11Kelas 12mathTrigonometri

Jika 0<x<(pi)/(2) dan 2 sin ^(2) x+cos ^(2) x=(34)/(25)

Pertanyaan

Jika \(0<x<\frac{\pi}{2}\) dan \(2 \sin^2 x + \cos^2 x = \frac{34}{25}\) maka nilai \(\tan x\)?

Solusi

Verified

\(\tan x = \frac{3}{4}\)

Pembahasan

Kita diberikan persamaan trigonometri \(2 \sin^2 x + \cos^2 x = \frac{34}{25}\) dengan rentang \(0 < x < \frac{\pi}{2}\). Kita perlu mencari nilai \(\tan x\). Menggunakan identitas \(\sin^2 x + \cos^2 x = 1\), kita bisa mengganti \(\cos^2 x = 1 - \sin^2 x\) ke dalam persamaan: \(2 \sin^2 x + (1 - \sin^2 x) = \frac{34}{25}\) \(\sin^2 x + 1 = \frac{34}{25}\) \(\sin^2 x = \frac{34}{25} - 1\) \(\sin^2 x = \frac{34 - 25}{25}\) \(\sin^2 x = \frac{9}{25}\) Karena \(0 < x < \frac{\pi}{2}\), \(\sin x\) bernilai positif. Maka: \(\sin x = \sqrt{\frac{9}{25}} = \frac{3}{5}\) Selanjutnya, kita bisa mencari \(\cos x\) menggunakan \(\sin^2 x + \cos^2 x = 1\): \((\frac{3}{5})^2 + \cos^2 x = 1\) \(\frac{9}{25} + \cos^2 x = 1\) \(\cos^2 x = 1 - \frac{9}{25}\) \(\cos^2 x = \frac{16}{25}\) Karena \(0 < x < \frac{\pi}{2}\), \(\cos x\) juga bernilai positif. Maka: \(\cos x = \sqrt{\frac{16}{25}} = \frac{4}{5}\) Terakhir, kita hitung \(\tan x\): \(\tan x = \frac{\sin x}{\cos x} = \frac{3/5}{4/5} = \frac{3}{4}\)

Buka akses pembahasan jawaban

Topik: Persamaan Trigonometri
Section: Identitas Trigonometri

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