Partial Fraction Expansion
Given the equation:
$\frac{1}{(x-1)(x-2)}+\frac{1}{(x-2)(x-3)}+\frac{1}{(x-3)(x-4)}=\frac{2}{3}$
We can expand the partial fractions to simplify the equation.
Step 1: Partial Fraction Expansion
Let's start by expanding the first fraction:
$\frac{1}{(x-1)(x-2)}=\frac{A}{x-1}+\frac{B}{x-2}$
Multiplying both sides by $(x-1)(x-2)$, we get:
$1=A(x-2)+B(x-1)$
Equating coefficients, we get:
$A=-1, B=1$
So,
$\frac{1}{(x-1)(x-2)}=\frac{-1}{x-1}+\frac{1}{x-2}$
Similarly, let's expand the second fraction:
$\frac{1}{(x-2)(x-3)}=\frac{C}{x-2}+\frac{D}{x-3}$
Multiplying both sides by $(x-2)(x-3)$, we get:
$1=C(x-3)+D(x-2)$
Equating coefficients, we get:
$C=1, D=-1$
So,
$\frac{1}{(x-2)(x-3)}=\frac{1}{x-2}-\frac{1}{x-3}$
Finally, let's expand the third fraction:
$\frac{1}{(x-3)(x-4)}=\frac{E}{x-3}+\frac{F}{x-4}$
Multiplying both sides by $(x-3)(x-4)$, we get:
$1=E(x-4)+F(x-3)$
Equating coefficients, we get:
$E=-1, F=1$
So,
$\frac{1}{(x-3)(x-4)}=\frac{-1}{x-3}+\frac{1}{x-4}$
Step 2: Combine the Expanded Fractions
Now, let's combine the expanded fractions:
$\frac{-1}{x-1}+\frac{1}{x-2}+\frac{1}{x-2}-\frac{1}{x-3}-\frac{1}{x-3}+\frac{1}{x-4}=\frac{2}{3}$
Combine like terms:
$\frac{-1}{x-1}+\frac{2}{x-2}-\frac{2}{x-3}+\frac{1}{x-4}=\frac{2}{3}$
Step 3: Simplify the Equation
Simplifying the equation, we get:
$\frac{-1}{x-1}+\frac{2}{x-2}-\frac{2}{x-3}+\frac{1}{x-4}=\frac{2}{3}$
This is the simplified equation.