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Question Number 111023 by mohammad17 last updated on 01/Sep/20

∫((sin(x))/(1+x^2 ))dx

sin(x)1+x2dx

Commented by mohammad17 last updated on 01/Sep/20

help me sir

helpmesir

Answered by mathdave last updated on 02/Sep/20

solution   series form of (1/(1+x^2 ))=(−1)^n Σ_(n=0) ^∞ x^(2n)   I=∫((sinx)/(1+x^2 ))dx=(−1)^n Σ_(n=0) ^∞ ∫x^(2n) sinxdx  using IBP  let u=x^(2n) ,du=2x^(2n) and  ∫dv=∫sinxdx,v=−cosx  but ∫udv=uv−∫vdu  I=(−1)^n Σ_(n=0) ^∞ [(−x^(2n) cosx+2∫x^(2n) cosxdx]  I=−(−1)^n Σ_(n=0) ^∞ x^(2n) cosx+2(−1)^n Σ_(n=0) ^∞ ∫x^(2n) cosxdx  I=−(−1)^n Σ_(n=0) ^∞ x^(2n) cosx+2(−1)^n Σ_(n=0) ^∞ [x^(2n) sinx−2∫x^(2n) sinxdx]  I=−(−1)^n Σ_(n=0) ^∞ x^(2n) cosx+2(−1)^n Σ_(n=0) ^∞ x^(2n) sinx−4I  I+4I=(−1)^n Σ_(n=0) ^∞ x^(2n) [2sinx−cosx]  ∵I=∫((sinx)/(1+x^2 ))dx=(((−1)^n Σ_(n=0) ^∞ x^(2n) )/5)[2sinx−cosx]  mathdave(02/09/2020)

solutionseriesformof11+x2=(1)nn=0x2nI=sinx1+x2dx=(1)nn=0x2nsinxdxusingIBPletu=x2n,du=2x2nanddv=sinxdx,v=cosxbutudv=uvvduI=(1)nn=0[(x2ncosx+2x2ncosxdx]I=(1)nn=0x2ncosx+2(1)nn=0x2ncosxdxI=(1)nn=0x2ncosx+2(1)nn=0[x2nsinx2x2nsinxdx]I=(1)nn=0x2ncosx+2(1)nn=0x2nsinx4II+4I=(1)nn=0x2n[2sinxcosx]I=sinx1+x2dx=(1)nn=0x2n5[2sinxcosx]mathdave(02/09/2020)

Commented by mohammad17 last updated on 02/Sep/20

you are an awesome person thank you sir

youareanawesomepersonthankyousir

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