Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Indefinite Integration

Question:

If $\int\frac{x^4}{x-2}dx= px + qx^2 + rx^3+ sx^4+ t\log|x - 2|+ C$, where $C$ is an arbitrary constant and $p, q, r, s, t $ are real numbers, then the correct arrangement of $p, q, r, s, t$ is

Options:

$p>q>r>s>t$

$q>r>p>t>s$

$r>t>s>p>q$

$t>p>q>r>s$

Correct Answer:

$t>p>q>r>s$

Explanation:

The correct answer is Option (4) → $t>p>q>r>s$

Given:

$\int \frac{x^4}{x - 2} \, dx = px + qx^2 + rx^3 + sx^4 + t\log|x - 2| + C$

Use polynomial division:

Divide $x^4$ by $(x - 2)$:

$\begin{align*} &\frac{x^4}{x - 2} = x^3 + 2x^2 + 4x + 8 + \frac{16}{x - 2} \\ \Rightarrow\ &\int \frac{x^4}{x - 2} dx = \int (x^3 + 2x^2 + 4x + 8 + \frac{16}{x - 2}) dx \\ =\ &\frac{x^4}{4} + \frac{2x^3}{3} + 2x^2 + 8x + 16\log|x - 2| + C \end{align*}$

Comparing with:

$px + qx^2 + rx^3 + sx^4 + t\log|x - 2| + C$

Match coefficients:

  • $s = \frac{1}{4}$
  • $r = \frac{2}{3}$
  • $q = 2$
  • $p = 8$
  • $t = 16$

Descending order of $(p, q, r, s, t)$ is:

${t > p > q > r > s}$