Wednesday, July 8, 2015

`(x^2 + x + 2)/(x^2 + 2)^2` Write the partial fraction decomposition of the rational expression.

`(x^2+x+2)/(x^2+2)^2`


Let`(x^2+x+2)/(x^2+2)^2=(Ax+B)/(x^2+2)+(Cx+D)/(x^2+2)^2`


`(x^2+x+2)/(x^2+2)^2=((Ax+B)(x^2+2)+Cx+D)/(x^2+2)^2`


`:.(x^2+x+2)=(Ax+B)(x^2+2)+Cx+D`


`x^2+x+2=Ax^3+2Ax+Bx^2+2B+Cx+D`


`x^2+x+2=Ax^3+Bx^2+(2A+C)x+2B+D`


Equating coefficients of like terms gives,


`A=0`


`B=1`


`2A+C=1`


`2B+D=2`


substituting the values of A and B in the above equations,


`2(0)+C=1`


`C=1`


`2(1)+D=2`


`2+D=2`


`D=2-2`


`D=0`


`:.(x^2+x+2)/(x^2+2)^2=1/(x^2+2)+x/(x^2+2)^2`

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