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Question Number 201452 by tri26112004 last updated on 06/Dec/23

Answered by Calculusboy last updated on 06/Dec/23

∫x^(−2) e^(−4x) dx  Solution:  by using IBP  let u=e^(−4x)    du=−4e^(−4x) dx  dv=x^(−2)    v=−x^(−1)   I=uv−∫vdudx  I=−x^(−1) e^(−4x) −4∫x^(−1) e^(−4x) dx   (take Ibp_2 )  I_1 =∫x^(−1) e^(−4x) dx   let u=e^(−4x)   du=−4e^(−4x) dx  dv=x^(−1)    v=(x^(−1+1) /(−1+1))  I_1 =uv−∫vdudx  I_1 =0   then  I=−x^(−1) e^(−4x) −4I_1   I=−x^(−1) e^(−4x) +C

x2e4xdxSolution:byusingIBPletu=e4xdu=4e4xdxdv=x2v=x1I=uvvdudxI=x1e4x4x1e4xdx(takeIbp2)I1=x1e4xdxletu=e4xdu=4e4xdxdv=x1v=x1+11+1I1=uvvdudxI1=0thenI=x1e4x4I1I=x1e4x+C

Commented by Calculusboy last updated on 06/Dec/23

but am not sure sha

butamnotsuresha

Commented by Frix last updated on 07/Dec/23

dv=x^(−1)  ⇒ v=ln x

dv=x1v=lnx

Commented by Calculusboy last updated on 08/Dec/23

oh thanks for reminding me sir

ohthanksforremindingmesir

Answered by Mathspace last updated on 07/Dec/23

I=∫ (e^(−4x) /x^2 )dx by parts  I=−(1/x)e^(−4x) −∫(−(1/x))(−4)e^(−4x) dx  =−(e^(−4x) /x)−∫ (e^(−4x) /x)dx  =−(e^(−4x) /x)−∫(1/x)Σ_(n=0) ^∞ (((−4x)^n )/(n!))dx  =−(e^(−4x) /x)−Σ_(n=0) ^∞ (((−4)^n )/(n!))∫x^(n−1) dx  =−(e^(−4x) /x)−Σ_(n=0) ^∞ (((−4)^n )/(n(n!))) x^n

I=e4xx2dxbypartsI=1xe4x(1x)(4)e4xdx=e4xxe4xxdx=e4xx1xn=0(4x)nn!dx=e4xxn=0(4)nn!xn1dx=e4xxn=0(4)nn(n!)xn

Commented by Calculusboy last updated on 11/Dec/23

sir,i think you forget the 4  you can check your solution back

sir,ithinkyouforgetthe4youcancheckyoursolutionback

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