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    Can anyone explain how to integrate sec^2(x)tanx ? thanks
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    (Original post by coconut64)
    Can anyone explain how to integrate sec^2(x)tanx ? thanks
    Note that the derivative of tanx is sec^2x, so you can apply the reverse chain rule


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    (Original post by coconut64)
    Can anyone explain how to integrate sec^2(x)tanx ? thanks
    Think about what differentiates to give something that looks similar.
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    You could recognize that sec^2x is the derivative of tan x or use a u substitution, let u = tanx

    (Original post by coconut64)
    Can anyone explain how to integrate sec^2(x)tanx ? thanks
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    (Original post by NotNotBatman)
    You could recognize that sec^2x is the derivative of tan x or use a u substitution, let u = tanx
    I get how to obtain the sec^2x part but what about the tanx part? Also what about secx as this gives me secxtanx...

    Thanks
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    (Original post by SeanFM)
    Think about what differentiates to give something that looks similar.
    I know that secx gives secxtanx but this doesn't give me sec^2 x though...

    Thanks
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    (Original post by coconut64)
    I get how to obtain the sec^2x part but what about the tanx part? Also what about secx as this gives me secxtanx...

    Thanks
    \frac{d}{dx}(tan(x)) =sec^2(x), so what does differentiating tan^2x result in?
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    (Original post by coconut64)
    I know that secx gives secxtanx but this doesn't give me sec^2 x though...

    Thanks
    it's been given above, but it was tanx that you should be particularly interested in. It's worth looking at a list of all of those ones (sec, tan cosex, cot.. and what they differentiate to if you're stuck)
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    (Original post by coconut64)
    I know that secx gives secxtanx but this doesn't give me sec^2 x though...

    Thanks
    (Original post by SeanFM)
    it's been given above, but it was tanx that you should be particularly interested in. It's worth looking at a list of all of those ones (sec, tan cosex, cot.. and what they differentiate to if you're stuck)
    Using the fact that differentiating sec x gives sec x tan x is an alternative to using the derivative of tan x.

    I've always liked integrals that give you more than one answer and they look completely different at first sight (like sin x cos x)
 
 
 
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