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Alfi asked in Sains & MatematikaMatematika · 8 years ago

nilai lim x=0 (x.tg 2x)/(1-cos 2x)?

2 Answers

Rating
  • Anonymous
    8 years ago
    Favorite Answer

    k = (x tg 2x)/(1 - cos 2x)

    lim x → 0

    k = (x tg 2x)/(1 - (1 - 2 sin² x))

    lim x → 0

    k = (x tg 2x)/(2 sin² x)

    lim x → 0

    k = (x/(2 sin x)) (sin 2x/cos 2x)(1/sin x)

    lim x → 0

    k = (x/(2 sin x)) (2 sin x cos x/sin x)(1/cos 2x)

    lim x → 0

    k = (x/(2 sin x)) (2 cos x)(1/cos 2x)

    lim x → 0

    k = (1/2)(2)

    k = 1

  • 8 years ago

    lim x→0 (x.tan 2x)/(1 - cos 2x)

    = lim x→0 (x.tan 2x)/{1 – (1 – 2 sin² x)}

    = lim x→0 (x.tan 2x)/ 2 sin² x

    = lim x→0 (x.tan 2x) / (2 sin x.sin x)

    = (1.2)/(2.1.1)

    = 2/2

    = 1

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