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smith.greme (9)

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Find the value of


    
juana (44)

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take xn +1 as t.




 






 




 


differentiating, n xn-1 dx = dt




 






 




 


substitute.




 






 




 


we get   dt/n xn-1 x (t)




 






 




 


=dt/n xn t




 






 




 


=dt/n t (t-1)




 






 




 


now you can integrate using partial fractions.




 


At + B(t-1)=1




 


A=-1, B=1




 


so, we get (-1) dt/t +dt/(t-1)




 


= -ln t + ln(t-1)




 


= - ln (xn + 1) + ln xn +c


=ln [(xn + 1)/xn] = ln [1+1/xn] +c

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rohitkuruvila (299)

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is it  ln(x)  - { [ ln|xn+1| ] / n }                                                                                                                                                                                                                                                                                                                                                            

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vnkt.swaroop (317)

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let xpowern+1=t.


on diffrentiating we getnxpowern/x=dt/dx.


dx/x=dt/nxpowern.


=integral 1/t(t-1).Using partial fractions we get the answer as


log(xpowern)-log(xpowern+1).

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krishna.gopal (2397)

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Well done Juana. But you missed 1/n in between. Multiply your answer with 1/n to get right answer which is same as that of rohit.

Krishna Gopal Singh
B.Tech Chemical Engg
IIT Delhi 2002
Currently doing PhD from IIT Delhi
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nitish971 (5)

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Put logx=t.


dx/x = dt


so xn = e(nt)


the integral becomes.....dt/(ent + 1)


Multiply the numerator and denominator by e-nt so that it gets converted to the form f'(x)/f(x).

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feynmann (2236)

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multiply Nr. and Dr. bu x^(n-1) and then put x^n = t

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