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e-x-1-x-2-dx-




Question Number 44654 by manish00@gmail.com last updated on 02/Oct/18
∫(e^x /(1+x^2 ))dx=?
ex1+x2dx=?
Commented by maxmathsup by imad last updated on 02/Oct/18
changement x=tanθ give I =∫  (e^(tanθ) /(1+tan^2 θ)) (1+tan^2 θ)dθ  = ∫ e^(tanθ) dθ  =∫ (Σ_(n=0) ^∞    (((tanθ)^n )/(n!)))dθ  =Σ_(n=0) ^∞  (1/(n!)) ∫ tan^n dθ   and A_n =∫ tan^n θdθ can be calculated by recurrence ...
changementx=tanθgiveI=etanθ1+tan2θ(1+tan2θ)dθ=etanθdθ=(n=0(tanθ)nn!)dθ=n=01n!tanndθandAn=tannθdθcanbecalculatedbyrecurrence
Commented by maxmathsup by imad last updated on 02/Oct/18
we have e^x  =Σ_(n=0) ^∞   (x^n /(n!)) ⇒ ∫ (e^x /(1+x^2 ))dx = ∫  (1/(1+x^2 )) (Σ_(n=0) ^∞   (x^n /(n!)))dx  =Σ_(n=0) ^∞   (1/(n!)) ∫ (x^n /(1+x^2 )) dx =Σ_(n=0) ^∞    (A_n /(n!))  with A_n = ∫  (x^n /(1+x^2 ))dx ....
wehaveex=n=0xnn!ex1+x2dx=11+x2(n=0xnn!)dx=n=01n!xn1+x2dx=n=0Ann!withAn=xn1+x2dx.
Commented by maxmathsup by imad last updated on 02/Oct/18
i think this integral can t be calculated by elementary functions...
ithinkthisintegralcantbecalculatedbyelementaryfunctions
Commented by arvinddayama01@gmail.com last updated on 03/Oct/18
Thanku  sir
Thankusir
Answered by tanmay.chaudhury50@gmail.com last updated on 02/Oct/18
is it feasible...
isitfeasible

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