How do you write the partial fraction decomposition of the rational expression # (x^3 - 6x^2 + 11x - 6) / (4x^3 - 28x^2 + 56x - 32) #?
1 Answer
Mar 21, 2016
#(x^3-6x^2+11x-6)/(4x^3-28x^2+56x-32)=1/4+1/(4(x-4))#
with exclusions
Explanation:
Let us factor the numerator and denominator first:
#x^3-6x^2+11x-6#
#=(x-1)(x^2-5x+6)#
#=(x-1)(x-2)(x-3)#
#4x^3-28x^2+56x-32#
#=4(x^3-7x^2+14x-8)#
#=4(x-1)(x^2-6x+8)#
#=4(x-1)(x-2)(x-4)#
So:
#(x^3-6x^2+11x-6)/(4x^3-28x^2+56x-32)#
#=(color(red)(cancel(color(black)((x-1))))color(red)(cancel(color(black)((x-2))))(x-3))/(4color(red)(cancel(color(black)((x-1))))color(red)(cancel(color(black)((x-2))))(x-4))#
#=(x-3)/(4(x-4))#
#=(x-4+1)/(4(x-4))#
#=1/4+1/(4(x-4))#
with exclusions