Matematika

Pertanyaan

1 limit fungsi
[tex]1 \: \frac{lim}{x - > 1 } \: \: \: \: 7x \sqrt{2x - 1} \\ \\ 2 \: \: \frac{lim}{x - > 0} \: \: \: \: \frac{ \sin(2x) }{ \sin(8x) }[/tex]
[tex]3 \frac{lim}{x - > 0} \: \: \: \: \frac{ \tan \: x - \sin }{ {x}^{3} } \\ \\ 4 \: \: \: \frac{lim}{x - > 0 } \: \: \: \frac{ {x}^{2} + 2x - 8}{x + 4} \: [/tex]

1 Jawaban

  • jawab

    1. limit (x ->1) 7x √(2x - 1)
    subx = 1--> 7(1) √(2.1-1) = 7√1 = 7

    2. limit (x -> 0)  (sin 2x)/ (sin 8x)
    = 2x/8x
    = 1/4

    3. limit (x ->0) (tan x - sin x)/(x³) = 

    = sin x/ cosx  - sin x / (x³)
    = (sin x - sin x cos x) / (x³. cos x)
    = sin x (1 - cos x) / (x³. cos x)
    = sin x (1 - (1 - 2 sin² ¹/₂ x)) / (x³. cos x)
    = sin x (2 sin² ¹/₂ x) / (x³. cos x)
    = x(2)(1/2 x)(1/2 x) /x³ . 1/cos x
    = 1/2 x³/x³.  (1/cos x)
    = 1/ (2 cos x)
    x= 0
    limit  = 1/ 2 cos.0 = 1/2


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