Precalculus, Chapter 7, 7.4, Section 7.4, Problem 49

A bit more extension for my above solution
Now in the above expression we need to simplify the
(2x-1)/(x^3 + 2x^2 + x) It is as follows
(2x-1)/(x^3 + 2x^2 + x) = (2x-1)/(x(x+1)^2)
(2x-1)/(x(x+1)^2)= (a/x) + (b/(x+1))+(c/(x+1)^2))
on simplification we get(2x-1)= (a(x+1)^2)+(bx(x+1))+cx
As the roots of the denominator (x(x+1)^2) are 0 , -1 . We can solve the unknown parameters by plugging the values of x .
when x=0 , we geta=-1 when x=(-1) we get c=3
As we know the a,c values , we can find the value of b as
2x-1 = (-1)(x+1)^2 + bx(x+1)+3x 2x-1 = bx^2+x+bx-x^2-1 2x-1 = x^2(b-1)+x(b+1)-1 on comparing we get b+1 =2 => b=1 so, (2x-1)/(x^3 + 2x^2 + x) = ((-1)/x)+(1/(x+1))+(3/(x+1^2)) so, the partial fraction for
(x^4 + 2x^3 + 4x^2 + 8x + 2)/(x^3 + 2x^2 + x) = x+ (3/x)+ (2x-1)/(x^3 + 2x^2 + x)
=x+ (3/x)+ ((-1)/x)+(1/(x+1))+(3/(x+1^2)) = x+(2/x)+(1/(x+1))+(3/(x+1)^2).

Comments

Popular posts from this blog

Single Variable Calculus, Chapter 3, 3.6, Section 3.6, Problem 34

In “Fahrenheit 451,” what does Faber mean by “Those who don’t build must burn. It’s as old as history and juvenile delinquents”?

In what ways might RFID technology be used to serve customers better? What problems might arise? Do you think that the technology might be valuable when implanted in animals or people?