Respuesta :
Answer:
8/(x + 2) - 4/(x + 6)
Step-by-step explanation:
4x + 40 = Ax + 6A + Bx + 2B
Equating coefficients of x
4 = A + B (1)
Equating constant terms:
40 = 6A + 2B (2)
Multiply equation (1) by -2:
-8 = -2A - 2B .. (3)
Add (2) and (3):
32 = 4A
A = 32/4
A = 8.
4 = 8 + B
B = 4 - 8
B = -4.
The decomposition of the given partial fraction in terms of x is [tex]\frac{4x+40}{(x+2)(x+6)} =\frac{8}{(x+2)}-\frac{4}{(x+6)}[/tex].
What is partial fraction?
The partial fraction is the result of writing a rational expression as the sum of two or more fractions.
According to the given question.
We have a partial fraction
[tex]\frac{4x+40}{(x+2)(x+6)} =\frac{A}{(x+2)} +\frac{B}{(x+6)}[/tex]
We have to decompose the above partial fraction in terms of x.
The above partial fraction can be written as
[tex]\frac{4x+40}{(x+2)(x+6)} =\frac{A(x+6)+B(x+2)}{(x+2)(x+6)}[/tex]
⇒[tex]4x+40 = A(x+6)+B(x+2)[/tex]
⇒[tex]4x + 40 = Ax + 6A + Bx + 2B[/tex]
⇒[tex]4x + 40 = x(A+B) +6A + 2B...(i)[/tex]
On comparing the coefficient of x and the constant terms.
[tex]A+B = 4..(ii)[/tex]
⇒[tex]A = 4 - B[/tex]
and, [tex]6A+2B = 40..(iii)[/tex]
⇒[tex]2(3A+B) = 40[/tex]
Substitute the value of A in (iii)
⇒[tex]2(3A+B) = 40[/tex]
⇒[tex]3A+B = 20[/tex]
⇒[tex]3(4-B)+B = 20[/tex]
⇒[tex]12 - 3B +B = 20[/tex]
⇒[tex]12 - 2B = 20[/tex]
⇒[tex]-2B = 8[/tex]
⇒[tex]B = -4[/tex]
So, [tex]A = 4-(-4) = 8[/tex]
Substitute the value of A and B in the given partial fraction.
⇒[tex]\frac{4x+40}{(x+2)(x+6)} =\frac{8}{(x+2)}-\frac{4}{(x+6)}[/tex]
Hence, the decomposition of the given partial fraction in terms of x is [tex]\frac{4x+40}{(x+2)(x+6)} =\frac{8}{(x+2)}-\frac{4}{(x+6)}[/tex].
Find out the more information about the partial fraction here:
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