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dx-sin2x-sec-x-




Question Number 68116 by aliesam last updated on 05/Sep/19
∫(dx/(sin2x−sec(x)))
dxsin2xsec(x)
Commented by MJS last updated on 06/Sep/19
look at question 68141
lookatquestion68141
Answered by MJS last updated on 05/Sep/19
∫(dx/(sin 2x −sec x))=       [t=sin x → dt=(dt/(cos x))]  =−(1/2)∫(dt/(t^3 −t+(1/2)))=−(1/2)∫(dt/((t−α)(t−β)(t+γ)))  now decompose and integrate  at the end solve t^3 −t+(1/2)=0 to get the  constant factors
dxsin2xsecx=[t=sinxdt=dtcosx]=12dtt3t+12=12dt(tα)(tβ)(t+γ)nowdecomposeandintegrateattheendsolvet3t+12=0togettheconstantfactors
Commented by mind is power last updated on 05/Sep/19
cardan
cardan
Commented by MJS last updated on 05/Sep/19
what does “cardan” mean?
whatdoescardanmean?
Commented by mind is power last updated on 05/Sep/19
cardan is one way to solve  algebric equation of degre 3 sorry fir my english
cardanisonewaytosolvealgebricequationofdegre3sorryfirmyenglish
Commented by MJS last updated on 06/Sep/19
of course! you mean Cardano′s method, you  are right. I read “cardan” and the only thing  that came to my mind was the “cardan shaft   drive”... haha, blame it on me...
ofcourse!youmeanCardanosmethod,youareright.Ireadcardanandtheonlythingthatcametomymindwasthecardanshaftdrivehaha,blameitonme
Commented by mind is power last updated on 05/Sep/19
yeah sorry im french my english is not verry good
yeahsorryimfrenchmyenglishisnotverrygood
Commented by MJS last updated on 06/Sep/19
no problem, I'm from Austria... I had 4 years of French in school but that had been 30 years ago... Je peux encore comprendre partiellement le français écrit, mais je ne comprends plus la langue parlée ...

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