Question
Evaluate the following intregals:
$\int\frac{\text{x}^3}{(\text{x}-1)(\text{x}-2)(\text{x}-3)}\ \text{dx}$

Answer

Let $\text{I}=\int\frac{\text{x}^3}{(\text{x}-1)(\text{x}-2)(\text{x}-3)}\ \text{dx}$
$=\int1+\frac{6\text{x}^2-9\text{x}+6}{(\text{x}-1)(\text{x}-2)(\text{x}-3)}\ \text{dx}$
Let $\frac{6\text{x}^2-9\text{x}+6}{(\text{x}-1)(\text{x}-2)(\text{x}-3)}=\frac{\text{A}}{\text{x}-1}+\frac{\text{B}}{\text{x}-2}+\frac{\text{C}}{\text{x}-3}$
$\text{x}\Rightarrow6\text{x}^2-11+6=\text{A}(\text{x}-2)(\text{x}-3)\\+\text{B}(\text{x}-1)(\text{x}-3)+\text{C}(\text{x}-1)(\text{x}-2)$
put x = 1
$\Rightarrow1=2\text{A}\Rightarrow\text{A}=\frac{1}{2}$
put x = 2
$\Rightarrow8=-\text{B}\Rightarrow\text{B}=-8$
put x = 3
$\Rightarrow27=2\text{C}\Rightarrow\text{C}=\frac{27}{2}$
Thus,
$\text{I}=\int\text{dx}+\frac{1}{2}\int\frac{\text{dx}}{\text{x}-1}-8\int\frac{\text{dx}}{\text{x}-2}+\frac{27}{2}\int\frac{\text{dx}}{\text{x}-3}$
$=\text{x}+\frac{1}{2}\log|\text{x}-1|-8\log|\text{x}-2|+\frac{27}{2}\log|\text{x}-3|+\text{C}$
Hence,
$\text{I}=\text{x}+\frac{1}{2}\log|\text{x}-1|-8\log|\text{x}-2|+\frac{27}{2}\log|\text{x}-3|+\text{C}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Prove the following :

$\tan ^{-1} \sqrt{\frac{1-\cos \theta}{1+\cos \theta}}=\frac{\theta}{2}$, if $\theta \in(0, \pi)$

Find the points of discontinuity, if any of the following function:
$\text{f(x)}=\begin{cases}\frac{\sin3\text{x}}{\text{x}},&\text{if }\text{ x}\neq0\\4,&\text{if }\text{ x}=0\end{cases}$
Find the area of the region in the first quadrant bounded by the circle $x^2+y^2=4$ and the

X-axis and the line x = y√3.

Find the equations of the tangent and the normal to the following curves at the indicated points.
$y = x^4 - bx^3 + 13x^2 - 10x + 5$ at $(0, 5)$
Without expanding, show that the values of the following determinant are zero: $\begin{vmatrix}(2^{x}+2^{-x})^2&(2^{x}-2^{-x})^2&1\\(3^{x}+3^{-x})^2&(3^{x}-3^{-x})^2&1\\(4^{x}+4^{-x})^2&(4^{x}-4^{-x})^2&1\end{vmatrix}$
Let S be the set of all real numbers except -1 and let '*' be an operation defined by a * b = a + b + ab for all a, b ∈ S. Determine whether '*' is a binary operation on S. If yes, check its commutativity and associativity. Also, solve the equation (2 * x) * 3 = 7.
Solve the following differential equations:
$2(\text{y}+3)-\text{xy}\frac{\text{dy}}{\text{dx}}=0,\text{y}(1)=-2$
Find $\frac{\text{dy}}{\text{dx}}$ in the following cases:
$y^3 - 3xy^2 = x^3 + 3x^2y$
If $\text{A}=\begin{bmatrix}0&0\\4&0\end{bmatrix},$ find $A^{16}.$
 A particle moves along the curve $y=x^2+2 x$. At what point(s) on the curve are the $x$ and $y$ coordinates of the particle changing at the same rate?