MCQ
Choose the correct answer from given four options in each of the Exercise:
The determinant $\begin{vmatrix}\text{b}^2-\text{ab}&\text{b}-\text{c}&\text{bc}-\text{ac}\\\text{ab}-\text{a}^2&\text{a}-\text{b}&\text{b}^2-\text{ab}\\\text{bc}-\text{ac}&\text{c}-\text{a}&\text{ab}-\text{a}^2\end{vmatrix}$ equals to:
  • A
    $abc(b - c)(c - a)(a - b)$
  • B
    $(b - c)(c - a)(a - b)$
  • C
    $(a + b + c)(b - c)(c - a)(a - b)$
  • D
    None of these

Answer

$\begin{vmatrix}\text{b}^2-\text{ab}&\text{b}-\text{c}&\text{bc}-\text{ac}\\\text{ab}-\text{a}^2&\text{a}-\text{b}&\text{b}^2-\text{ab}\\\text{bc}-\text{ac}&\text{c}-\text{a}&\text{ab}-\text{a}^2\end{vmatrix}=\begin{vmatrix}\text{b}(\text{b}-\text{a})&\text{b}-\text{c}&\text{c}(\text{b}-\text{a})\\\text{a}(\text{b}-\text{a})&\text{a}-\text{b}&\text{b}(\text{b}-\text{a})\\\text{c}(\text{b}-\text{a})&\text{c}-\text{a}&\text{a}(\text{b}-\text{a})\end{vmatrix}$
$=(\text{b}-\text{a})^2\begin{vmatrix}\text{b}&\text{b}-\text{c}&\text{c}\\\text{a}&\text{a}-\text{b}&\text{b}\\\text{c}&\text{c}-\text{a}&\text{a}\end{vmatrix}$
$[$on taking $(b - a)$ common from $C_1$ and $C_3$ each$]$
$=(\text{b}-\text{a})^2\begin{vmatrix}\text{b}-\text{c}&\text{b}-\text{c}&\text{c}\\\text{a}-\text{b}&\text{a}-\text{b}&\text{b}\\\text{c}-\text{a}&\text{c}-\text{a}&\text{a}\end{vmatrix}$ $\big[\because\ \text{C}_1\rightarrow\text{C}_1-\text{C}_3\big]$
$=0$
$[$Since, two columns $C_1$ and $C_2$ are identical, so the value of determinant is zero$]$

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

What is the value of $\int_{-1}^{1}\sin^3\text{x}\cos^2\text{xdx}?$
  1. $0$
  2. $1$
  3. $\frac{1}{2}$
  4. $2$
Let f(x) = |x| + |x - 1|, then:
  1. f(x) is continuous at x = 0, as well as at x = 1
  2. f(x) is continuous at x = 0, but not at x = 1
  3. f(x) is continuous at x = 0, but not at x = 0
  4. none of these
The function f(x) = e|x| is:
  1. Continuous everywhere but not differentiable at x = 0
  2. Continuous and differentiable everywhere
  3. Not continuous at x = 0
  4. None of these.
If $A$ is a $m \times n$ matrix such that $A B$ and $B A$ are both defined, then $B$ is an
The area of the region $\{(\text{x},\text{y}):\text{x}^2+\text{y}^2\leq1\leq\text{x}+\text{y}\}$ is:
If $x, y, z$ are different from zero and $\begin{vmatrix}1+\text{x}&1&1\\1&1+\text{y}&1\\1&1&1+\text{z}\end{vmatrix}=0,$ then the value $x^{-1} + y^{-1} + z^{-1}$ is:
Choose the correct answer from the given four options.
The vector in the direction of the vector $\hat{\text{i}}-2\hat{\text{j}}+2\hat{\text{k}}$ that has magnitude 9 is:
  1. $\hat{\text{i}}-2\hat{\text{j}}+2\hat{\text{k}}$
  2. $\frac{\hat{\text{i}}-2\hat{\text{j}}+2\hat{\text{k}}}{3}$
  3. $3(\hat{\text{i}}-2\hat{\text{j}}+2\hat{\text{k}})$
  4. $9(\hat{\text{i}}-2\hat{\text{j}}+2\hat{\text{k}})$
Given a curve $y=7 x-x^3$ and $x$ increases at the rate of 2 units per second. The rate at which the slope of the curve is changing, when $x=5$ is
What is the general solution of the differential equation $x^2 dy + y^2 dx = 0$?
$\frac{\text{d}^{20}}{\text{dx}^{20}}(2\cos\text{x}\cos3\text{x})=$
  1. $2^{20}(\cos2\text{x}-2^{20}\cos4\text{x})$
  2. $2^{20}(\cos2\text{x}+2^{20}\cos4\text{x})$
  3. $2^{20}(\sin2\text{x}+2^{20}\sin4^\text{x})$
  4. $2^{20}(\sin2\text{x}-2^{20}\sin4^\text{x})$