1. Formulate the basic algebraic identity by multiplying throughout by the denominator.
4x3+7x2−13x−2=A(x2+3)(x−1)+(Bx+C)(x−1)+D(x2+3)
2. Compare the coefficients of $x^3$ to find $A$.
Comparing coefficients of x3:
4=A
A=4
3. Substitute $x = 1$ to eliminate $A$, $B$, and $C$, and solve for $D$.
Let x=1:
4(1)3+7(1)2−13(1)−2=D(12+3)
4+7−13−2=4D
−4=4D
D=−1
4. Compare the coefficients of $x^2$ to find $B$.
Comparing coefficients of x2:
7=−A+B+D
7=−4+B−1
7=B−5
B=12
5. Substitute $x = 0$ (or compare constant terms) to find $C$.
Let x=0:
−2=A(3)(−1)+C(−1)+D(3)
−2=−3A−C+3D
−2=−3(4)−C+3(−1)
−2=−12−C−3
−2=−15−C
C=−13
答案A=4, B=12, C=−13, D=−1