Matematika

Pertanyaan

Jika f(x) = xcosx, maka f'(x + π/2) =...

1 Jawaban

  • Turunan Trigonometri

    f(x) = x cos x
    u = x --> u' = 1
    v = cos x --> v' = - sin x

    f = uv --> f' = u'v + uv'
    f' (x) = 1(cos x) + (x)(-sin x)
    f ' (x) = cos x - x sin x
    f ' (x + π/2) =  cos (x + π/2)  - (x+π/2) sin (x + π/2)
    f '(x + π/2) = - sin x - (x + π/2) cos x
    f '(x + π/2) = - sin x - x cos x - π/2 cos x

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