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Homework Help: How to integrate (sec x)^4, help please

  1. Jan 2, 2006 #1
    May i know how to integrate (sec x)^4 ??

    the answer is tan x + 1/3 (tan x)^3
     
  2. jcsd
  3. Jan 2, 2006 #2

    Pyrrhus

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    Homework Helper

    Try writing your integral as
    [tex] \int (\tan^{2} x + 1) \sec^{2} x dx [/tex]
     
  4. Jan 2, 2006 #3
    okok.......thanx
     
  5. Jan 2, 2006 #4
    try using [tex]u=tg(x)[/tex]
    [tex]du=\frac{dx}{cos^2(x)}[/tex]
    and [tex]\frac{1}{cos^2(x)}=1+tg^2(x)=1+u^2[/tex]
     
    Last edited: Jan 2, 2006
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