tentukan turunan limit fungsi trigonometri dari f(x) = sin x - sin x cos² x dengan f'(π/4)

<p>Jawaban &nbsp;&nbsp;<strong>¾√2&nbsp;</strong></p><p>&nbsp;</p><p><strong>Pembahasan&nbsp;</strong></p><p>f(x) = sin x - sin x. cos² x</p><p>f'(x) = cos x - cos x. cos² x - sin x. 2 cos x. -sin x</p><p>&nbsp; &nbsp; &nbsp; &nbsp; = cos x (1 - cos²x) + 2 sin² x. cos x</p><p>&nbsp;</p><p>f'(π/4) = cos (π/4). (1 - cos² π/4) + 2 sin²(π/4). cos π/4</p><p>&nbsp; &nbsp; = ½√2 × (1 - (½√2)²) + 2. (½√2)². ½√2</p><p>&nbsp; &nbsp; = ¼√2 + ½√2</p><p>&nbsp; &nbsp; = ¾√2</p>