Algebra PYQ — Page 5

A building has ground floor and 10 more floors. Nine persons enter in a lift at the ground floor. The lift goes up to the $10^{\text{th}}$ floor. The number of ways, in which any 4 persons exit at a floor and the remaining 5 persons exit at a different floor, if the lift does not stop at the first and the second floors, is equal to :

Let $A=\{z \in \mathbb{C}:|z-2| \leqslant 4\}$ and $B=\{z \in \mathbb{C}:|z-2|+|z+2|=5\}$. Then the max $\left\{\left|z_{1}-z_{2}\right|: z_{1} \in \mathrm{~A}\right.$ and $\left.z_{2} \in \mathrm{~B}\right\}$ is :

$\frac{6}{3^{26}}+\frac{10 \cdot 1}{3^{25}}+\frac{10 \cdot 2}{3^{24}}+\frac{10 \cdot 2^{2}}{3^{23}}+\ldots+\frac{10 \cdot 2^{24}}{3}$ is equal to :

The largest $\mathrm{n} \in \mathbf{N}$, for which $7^{\mathrm{n}}$ divides 101!, is :

The sum of all the roots of the equation $(x-1)^{2}-5|x-1|+6=0$, is :

Let the set of all values of $k \in \mathbb{R}$ such that the equation $z(\bar{z} + 2 + i) + k(2 + 3i) = 0$, $z \in \mathbb{C}$, has at least one solution, be the interval $[\alpha, \beta]$. Then $9(\alpha + \beta)$ is equal to:

Consider the system of linear equations in $x, y, z$: $x + 2y + tz = 0$, $6x + y + 5tz = 0$, $3x + t^2 y + f(t) z = 0$, where $f: \mathbb{R} \rightarrow \mathbb{R}$ is a differentiable function. If this system has infinitely many solutions for all $t \in \mathbb{R}$, then $f$

Let $a_{1}, a_{2}, a_{3}, \ldots$ be G.P. of increasing positive terms such that $a_{2} \cdot a_{3} \cdot a_{4}=64$ and $a_{1}+a_{3}+a_{5}=\frac{813}{7}$. Then $a_{3}+a_{5}+a_{7}$ is equal to :

Let $f$ be a polynomial function such that $\log_2(f(x)) = \left(\log_2\left(2+\dfrac{2}{3}+\dfrac{2}{9}+\ldots\infty\right)\right)\cdot\log_3\left(1+\dfrac{f(x)}{f(1/x)}\right)$, $x>0$ and $f(6)=37$. Then $\displaystyle\sum_{n=1}^{10}f(n)$ is equal to ________.

The coefficient of $x^2$ in the expansion of $\left(2x^2 + \dfrac{1}{x}\right)^{10}$, $x \neq 0$, is :

The sum $1 + \dfrac{1}{2}(1^2 + 2^2) + \dfrac{1}{3}(1^2 + 2^2 + 3^2) + \ldots$ upto 10 terms is equal to :

Let $x$ and $y$ be real numbers such that $50\left(\dfrac{2x}{1+3i} - \dfrac{y}{1-2i}\right) = 31 + 17i$, $i = \sqrt{-1}$. Then the value of $10(x - 3y)$ is :

Let $f(x)=\int \frac{7 x^{10}+9 x^{8}}{\left(1+x^{2}+2 x^{9}\right)^{2}} d x, x>0, \lim _{x \rightarrow 0} f(x)=0$ and $f(1)=\frac{1}{4}$. If $\mathrm{A}=\left[\begin{array}{ccc}0 & 0 & 1 \\ \frac{1}{4} & f^{\prime}(1) & 1 \\ \alpha^{2} & 4 & 1\end{array}\right]$ and $\mathrm{B}=\operatorname{adj}(\operatorname{adj} \mathrm{A})$ be such that $|\mathrm{B}|=81$, then $\alpha^{2}$ is equal to

Let n be the number obtained on rolling a fair die. If the probability that the system $x-\mathrm{n} y+z=6$ $x+(\mathrm{n}-2) y+(\mathrm{n}+1) z=8$ $(\mathrm{n}-1) y+z=1$ has a unique solution is $\frac{k}{6}$, then the sum of $k$ and all possible values of $n$ is :

The number of elements in the relation $\mathrm{R}=\left\{(x, y): 4 x^{2}+y^{2}<52, x, y \in \mathbf{Z}\right\}$ is

Let $f$ and $g$ be functions satisfying $f(x+y)=f(x) f(y), f(1)=7$ and $g(x+y)=g(x y), g(1)=1$, for all $x, y \in \mathbf{N}$. If $\sum_{x=1}^{\mathrm{n}}\left(\frac{f(x)}{\mathrm{g}(x)}\right)=19607$, then n is equal to:

Let $[\cdot]$ denote the greatest integer function. If the domain of the function $f(x) = \cos^{-1}\left(\dfrac{4x+2[x]}{3}\right)$ is $[\alpha, \beta]$, then $12(\alpha + \beta)$ is equal to:

Let $S = \{z \in \mathbb{C} : z^2 + \sqrt{6}\,iz - 3 = 0\}$. Then $\sum\limits_{z \in S} z^8$ is equal to :

If the system of equations $3 x+y+4 z=3$ $2 x+\alpha y-z=-3$ $x+2 y+z=4$ has no solution, then the value of $\alpha$ is equal to :

Let the circles $C_1 : |z| = r$ and $C_2 : |z - 3 - 4i| = 5$, $z \in \mathbb{C}$, be such that $C_2$ lies within $C_1$. If $z_1$ moves on $C_1$, $z_2$ moves on $C_2$ and $\min |z_1 - z_2| = 2$, then $\max |z_1 - z_2|$ is equal to:

Let $A = \{1, 4, 7\}$ and $B = \{2, 3, 8\}$. Then the number of elements, in the relation $R = \{((a_1, b_1), (a_2, b_2)) \in ((A \times B) \times (A \times B)) : a_1 + b_2 \text{ divides } a_2 + b_1\}$ is _______.

Let $A = \begin{bmatrix} \alpha & 1 & 2 \\ 2 & 3 & 0 \\ 0 & 4 & 5 \end{bmatrix}$ and $B = \begin{bmatrix} 1 & 0 & 0 \\ 0 & -5\alpha & 0 \\ 0 & 4\alpha & -2\alpha \end{bmatrix} + \text{adj}(A)$. If $\det(B)=66$, then $\det(\text{adj}(A))$ equals:

The sum $\dfrac{1^3}{1} + \dfrac{1^3 + 2^3}{1 + 3} + \dfrac{1^3 + 2^3 + 3^3}{1 + 3 + 5} + \cdots$ up to 8 terms, is:

$\left(\frac{1}{3}+\frac{4}{7}\right)+\left(\frac{1}{3^{2}}+\frac{1}{3} \times \frac{4}{7}+\frac{4^{2}}{7^{2}}\right)+\left(\frac{1}{3^{3}}+\frac{1}{3^{2}} \times \frac{4}{7}+\frac{1}{3} \times \frac{4^{2}}{7^{2}}+\frac{4^{3}}{7^{3}}\right)+\ldots$ upto infinite terms, is equal to