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decompose-the-folowing-fraction-at-R-x-1-F-x-x-3-1-x-6-2-G-x-x-2-1-x-3-x-2-x-1-2-




Question Number 67672 by Abdo msup. last updated on 30/Aug/19
decompose the folowing  fraction at R(x)  1)F(x)=(x^3 /(1−x^6 ))  2) G(x) =((x^2 +1)/(x^3 (x^2 +x+1)^2 ))
decomposethefolowingfractionatR(x)1)F(x)=x31x62)G(x)=x2+1x3(x2+x+1)2
Commented by Abdo msup. last updated on 30/Aug/19
1)F(x) =−(x^3 /((x^3 )^2 −1)) =−(x^3 /((x^3 −1)(x^3  +1)))  =((−x^3 )/((x−1)(x^2 +x+1)(x+1)(x^2 −x+1)))  =(a/(x−1)) +(b/(x+1)) +((cx +d)/(x^2  +x+1)) +((ex +f)/(x^2 −x +1))  a =lim_(x→1) (x−1)F(x) =−(1/(3.2.1)) =−(1/6)  b =lim_(x→−1) (x+1)F(x)=(1/((−2).3))=−(1/6) ⇒  F(x)=((−1)/(6(x−1)))−(1/(6(x+1))) +((cx+d)/(x^2  +x+1)) +((ex +f)/(x^2 −x+1))  F(−x) =−F(x) ⇒  (1/(6(x+1))) +(1/(6(x−1))) +((−cx+d)/(x^2 −x +1)) +((−ex +f)/(x^2  +x+1))  =(1/(6(x−1))) +(1/(6(x+1))) +((−cx −d)/(x^2  +x+1)) +((−ex−f)/(x^2 −x +1)) ⇒  ⇒ f=−d...
1)F(x)=x3(x3)21=x3(x31)(x3+1)=x3(x1)(x2+x+1)(x+1)(x2x+1)=ax1+bx+1+cx+dx2+x+1+ex+fx2x+1a=limx1(x1)F(x)=13.2.1=16b=limx1(x+1)F(x)=1(2).3=16F(x)=16(x1)16(x+1)+cx+dx2+x+1+ex+fx2x+1F(x)=F(x)16(x+1)+16(x1)+cx+dx2x+1+ex+fx2+x+1=16(x1)+16(x+1)+cxdx2+x+1+exfx2x+1f=d
Commented by Abdo msup. last updated on 30/Aug/19
⇒ F(x) =−(1/(6(x−1)))−(1/(6(x+1))) +((cx +d)/(x^2  +x+1)) +((ex−d)/(x^2 −x+1))  lim_(x→+∞) xF(x) =0 =−(1/3) +c+e ⇒e =(1/3)−c ⇒  F(x) =−(1/(6(x−1)))−(1/(6(x+1))) +((cx+d)/(x^2  +x+1)) +((((1/3)−c)x−d)/(x^2  −x +1))  to detrmine c and d  we?can calculate F(2) and  F(−2)...be?vontinued...
F(x)=16(x1)16(x+1)+cx+dx2+x+1+exdx2x+1limx+xF(x)=0=13+c+ee=13cF(x)=16(x1)16(x+1)+cx+dx2+x+1+(13c)xdx2x+1todetrminecanddwe?cancalculateF(2)andF(2)be?vontinued

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