Download App

Determinants — MATHS STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceMATHSDeterminants1 Mark
Question
Write the cofactor of the element $a_{31}$ in
$
A=\left(\begin{array}{lll}
3 & 2 & 6 \\
5 & 0 & 7 \\
3 & 8 & 5
\end{array}\right).
$
✓

Answer

(b) : We have, $A=\left(\begin{array}{lll}3 & 2 & 6 \\ 5 & 0 & 7 \\ 3 & 8 & 5\end{array}\right)$
Cofactor of $a_{31}=(-1)^{3+1}\left|\begin{array}{ll}2 & 6 \\ 0 & 7\end{array}\right|=14$

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

Explore more

More "M.C.Q (1 Marks)" from Determinants→Determinants — all question types→MATHS STD 12 Science question papers→Rajasthan Board STD 12 Science question papers→Rajasthan Board question paper generator→

Similar questions

If A and B are invertible matrices, then which of the following is not correct?
→
Area of the region bounded by the curve $y=x^2$ and the line $y=4$ is
→
A constant function f : A → B will be one-one if:
  1. n(A) = n(B)
  2. n(A) = 1
  3. n(B) = 1
  4. n(A) < n(B)
→
The radius of a circle is increasing at the rate of 0.4 cm/ s. The rate of increasing of its circumference is:
  1. $0.4\pi\text{cm}/\text{ s}.$
  2. $0.8\pi\text{cm}/\text{ s}.$
  3. $0.8\text{cm}/\text{ s}.$
  4. $\text{None of these}$
→
Let f : R → R be a function defined by $\text{f(x)}=\frac{\text{e}^{|\text{x}|}-\text{e}^{-\text{x}}}{\text{e}^\text{x}+\text{e}^{-\text{x}}}$ then f(x) is:
  1. One-one onto.
  2. One-one but not onto.
  3. Onto but not one-one.
  4. None of these.
→
The differential coefficient of $\text{f}(\log\text{x})$ w.r.t. x, where $\text{f(x)}=\log\text{x}$ is:
  1. $\frac{\text{x}}{\log\text{x}}$
  2. $\frac{\log\text{x}}{\text{x}}$
  3. $(\text{x}\log\text{x})^{-1}$
  4. $\text{None of these.}$
→
If the random variable X has the following distribution:
X: 0 1 2 3 4 5 6 7 8
P(X): a 3a 5a 7a 9a 11a 13a 15a 17a
then the value of a is:
  1. $\frac{7}{81}$
  2. $\frac{5}{81}$
  3. $\frac{2}{81}$
  4. $\frac{1}{81}$
→
If $\tan^{-1}(\cot\theta)=2\theta,$ then $\theta$ is equal to:
  1. $\frac{\pi}{3 }$
  2. $\frac{\pi}{4}$
  3. $\frac{\pi}{6}$
  4. None of these.
→
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
→
A problem in mathematics is given to 3 students whose chances of solving it are $\frac{1}{2}, \frac{1}{3}, \frac{1}{4}$. What is the probability that the problem is solved?
→