Question
Find which of the binary operations are commutative and which are associative.
Consider a binary operation * on N defined as a * b = a3 + b3. Choose the
correct answer.
  1. Is * both associative and commutative?
  2. Is * commutative but not associative?
  3. Is * commutative but not associative?
  4. Is * neither commutative nor associative?

Answer

a * b = a3 + b3 = b3 + a3 = b * a
$\therefore$ The operation is commutative.
Again, (a * b) * c = a * (a3 + b3) = a3(a3 + b3)3
And (a * b) * c= (a3 + b3) * c = (a3 + b3)3 + c3 $\neq\text{a}*(\text{b}*\text{c})$
$\therefore$ The operation * is not associative.
 Therefore, option (B) is correct.
  1. Is * commutative but not associative?

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

$\mathop \smallint \limits_2^4 \frac{{\log {x^2}}}{{\log {x^2} + {\rm{log}}\left( {36 - 12x + {x^2}} \right)}}\;dx = $
Which of the following differential equations has $\text{y} = \text{c}_1\text{e}^\text{x} + \text{c}_2\text{e}^{-\text{x}}$ as the general solution?
  1. $\frac{\text{d}^2\text{y}}{\text{dx}^2}+\text{y}=0$
  2. $\frac{\text{d}^2\text{y}}{\text{dx}^2}-\text{y}=0$
  3. $\frac{\text{d}^2\text{y}}{\text{dx}^2}+1=0$
  4. $\frac{\text{d}^2\text{y}}{\text{dx}^2}-1=0$
A line $m$ passes through the point $(-4,2,-3)$ and is parallel to line $n$, given by:
$\frac{-x-2}{4}=\frac{y+3}{-2}=\frac{2 z-6}{3}$
The vector equation of line $m$ is given by: $\vec{r}=(-4 \hat{i}+2 \hat{j}-3 \hat{k})+\lambda(p \hat{i}+q \hat{j}+r \hat{k})$, where $\lambda \in R$
Which of the following could be the possible values for $p, g$ and $r$ ?
If $\tan^{-1}\Big\{\frac{\sqrt{1+\text{x}^2}-\sqrt{1-\text{x}^2}}{\sqrt{1+\text{x}^2}+\sqrt{1-\text{x}^2}}\Big\}=\alpha,$ then x2 =
  1. $\sin2\alpha$
  2. $\sin\alpha$
  3. $\cos2\alpha$
  4. $\cos\alpha$
Choose the correct answer:
Area lying between the curves y2 = 4x and y = 2x is:
  1. $\frac23$
  2. $\frac13$
  3. $\frac14$
  4. $\frac34.$
Which of the following values of $\alpha$ satisfy the equation

$\left|\begin{array}{lll}(1+\alpha)^2 & (1+2 \alpha)^2 & (1+3 \alpha)^2 \\ (2+\alpha)^2 & (2+2 \alpha)^2 & (2+3 \alpha)^2 \\ (3+\alpha)^2 & (3+2 \alpha)^2 & (3+3 \alpha)^2\end{array}\right|=-648 \alpha$ ?

$(A)$ $-4$ $(B)$ $9$ $(C)$ $-9$ $(D)$ $4$

$\int\limits_{ - 2}^\pi  {\frac{{{{\sin }^2}x}}{{\left[ {\frac{x}{\pi }} \right] + \frac{1}{2}}}} \,dx$ is equal to               (where $[·]$ denotes the greatest integer function)
The function $f(x)=\left\{\begin{array}{l}\frac{\pi}{4}+\tan ^{-1} x,|x| \leq 1 \\ \frac{1}{2}(|x|-1),|x|>1\end{array}\right.$
If $\alpha ,\,\,\beta ,\,\gamma $ be the angles which a line makes with the positive direction of co-ordinate axes, then ${\sin ^2}\alpha + {\sin ^2}\beta + {\sin ^2}\gamma = $
Let a curve $y=y(x)$ be given by the solution of the differential equation

$\cos \left(\frac{1}{2} \cos ^{-1}\left(e^{-x}\right)\right) d x=\sqrt{e^{2 x}-1} \,d y$

If it intersects $y$-axis at $y=-1$, and the intersection point of the curve with $x$-axis is $(\alpha, 0)$ the $\mathrm{e}^{\alpha}$ is equal to $.....$