Maths

Mark the tick against the correct answer in the following: The solution set of the equation $\left|\begin{array}{ccc}3 \mathrm{x}-8 & 3 & 3 \\ 3 & 3 \mathrm{x}-8 & 3 \\ 3 & 3 & 3 \mathrm{x}-8\end{array}\right|=0$ is
A. $\left\{\frac{2}{3}, \frac{8}{3}\right\}$
B. $\left\{\frac{2}{3}, \frac{11}{3}\right\}$
C. $\left\{\frac{3}{2}, \frac{8}{3}\right\}$
D. None of these

Solution: Option(B) To find: Value of $x$ We have, $\left|\begin{array}{ccc}3 x-8 & 3 & 3 \\ 3 & 3 x-8 & 3 \\ 3 & 3 & 3 x-8\end{array}\right|=0$ Applying $\mathrm{R}_{1}...

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Mark the tick against the correct answer in the following: The solution set of the equation $\left|\begin{array}{ccc}\mathrm{x}-2 & 2 \mathrm{x}-3 & 3 \mathrm{x}-4 \\ \mathrm{x}-4 & 2 \mathrm{x}-9 & 3 \mathrm{x}-16 \\ \mathrm{x}-8 & 2 \mathrm{x}-27 & 2 \mathrm{x}-64\end{array}\right|=0$ is
A. $\{4\}$
B. $\{2,4\}$
C. $\{2,8\}$
D. $\{4,8\}$

Solution: Option(A) To find: Value of $x$ We have, $\left|\begin{array}{ccc}x-2 & 2 x-3 & 3 x-4 \\ x-4 & 2 x-9 & 3 x-16 \\ x-8 & 2 x-27 & 3 x-64\end{array}\right|=0$ Applying...

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Mark the tick against the correct answer in the following: The solution set of the equation $\left|\begin{array}{ccc}\mathrm{x} & 3 & 7 \\ 2 & \mathrm{x} & 2 \\ 7 & 6 & \mathrm{x}\end{array}\right|=0$ is
A. $\{2,-3.7\}$
B. $\{2,7 .-9\}$
C. $[-2,3,-7\}$
D. none of these

Solution: Option(C) To find: Value of $x$ We have, $\left|\begin{array}{lll}\mathrm{x} & 3 & 7 \\ 2 & \mathrm{X} & 2 \\ 7 & 6 & \mathrm{x}\end{array}\right|=0$ Applying...

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Mark the tick against the correct answer in the following: $\left|\begin{array}{lll}\mathrm{a} & 1 & \mathrm{~b}+\mathrm{c} \\ \mathrm{b} & 1 & \mathrm{c}+\mathrm{a} \\ \mathrm{c} & 1 & \mathrm{a}+\mathrm{b}\end{array}\right|=?$
A. $a+b+c$
B. $2(a+b+c)$
C. $4 \mathrm{abc}$
D. $a^{2} b^{2} c^{2}$

Solution: Option(C) To find: Value of $\left|\begin{array}{lll}a & 1 & b+c \\ b & 1 & c+a \\ c & 1 & a+b\end{array}\right|$ We have, $\left|\begin{array}{lll}a & 1 &...

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Mark the tick against the correct answer in the following: $\left|\begin{array}{lll} \mathrm{bc} & \mathrm{b}+\mathrm{c} & 1 \\ \mathrm{ca} & \mathrm{c}+\mathrm{a} & 1 \\ \mathrm{ab} & \mathrm{a}+\mathrm{b} & 1 \end{array}\right|=?$
A. $(a-b)(b-c)(c-a)$
B. $-(a-b)(b-c)(c-a)$
C. $(a+b)(b+c)(c+a)$
D. None of these

Solution: Option(A) To find: Value of $\left|\begin{array}{lll}\mathrm{bc} & \mathrm{b}+\mathrm{c} & 1 \\ \mathrm{ca} & \mathrm{a}+\mathrm{c} & 1 \\ \mathrm{ab} &...

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Mark the tick against the correct answer in the following: $\left|\begin{array}{ccc} \sin \alpha & \cos \alpha & \sin (\alpha+\delta) \\ \sin \beta & \cos \beta & \sin (\beta+\delta) \\ \sin \gamma & \cos \gamma & \sin (\gamma+\delta) \end{array}\right|=?$
A. 0
B. 1
C. $\sin (\alpha+\delta)+\sin (\beta+\delta)+\sin (\gamma+\delta)$
D. none of these

Solution: Option(A) To find: Value of $\left|\begin{array}{lll}\operatorname{sind} & \cos \alpha & \sin (\alpha+\bar{\delta}) \\ \sin \beta & \cos \beta & \sin (\beta+\bar{\delta})...

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Mark the tick against the correct answer in the following: $\left|\begin{array}{cc} a+i b & c+i d \\ -c+i d & a-i d \end{array}\right|=?$
A. $\left(a^{2}+b^{2}-c^{2}-d^{2}\right)$
B. $\left(a^{2}-b^{2}+c^{2}-d^{2}\right)$
C. $\left(a^{2}+b^{2}+c^{2}+d^{2}\right)$
D. none of these

Solution: Option(C) To find: Value of $\left|\begin{array}{cc}a+i b & c+i d \\ -c+i d & a-i b\end{array}\right|$ Formula used: $\mathrm{i}^{2}=-1$ We have, $\left|\begin{array}{cc}a+i b...

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Mark the tick against the correct answer in the following: $\left|\begin{array}{cc} \sin 23^{\circ} & -\sin 7^{\circ} \\ \cos 23^{\circ} & \cos 7^{\circ} \end{array}\right|=?$
A. $\frac{\sqrt{3}}{2}$
B. $\frac{1}{2}$
C. $\sin 16^{\circ}$
D. $\cos 16^{\circ}$

Solution: Option(B) To find: Value of $\left|\begin{array}{cc}\sin 23^{\circ} & -\sin 7^{\circ} \\ \cos 23^{\circ} & \cos 7^{\circ}\end{array}\right|$ Formula used: (i) $\sin (A+B)=\sin A...

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A manufacturer produces two Models of bikes – Model $\mathbf{X}$ and Model $\mathbf{Y}$. Model $\mathbf{X}$ takes 6 man-hours to make per unit, while Model Y takes 10 man-hours per unit. There is a total of 450 man-hour available per week. Handling and Marketing costs are Rs 2000 and Rs 1000 per unit for Models $X$ and $Y$ respectively. The total funds available for these purposes are Rs 80,000 per week. Profits per unit for Models $\mathrm{X}$ and $\mathrm{Y}$ are Rs 1000 and Rs 500 , respectively. How many bikes of each model should the manufacturer produce so as to yield a maximum profit? Find the maximum profit.

Solution: Let us take $\mathrm{x}$ an $\mathrm{y}$ to be the no. of models of bike produced by the manufacturer. From the question we have, Model $x$ takes 6 man-hours to make per unit Model $y$...

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Maximize $\mathrm{Z}=\mathbf{x}+\mathbf{y}$ subject to $\mathbf{x}+4 \mathbf{y} \leq \mathbf{8}, 2 \mathbf{x}+3 \mathbf{y} \leq \mathbf{1 2}, 3 \mathbf{x}+\mathbf{y} \leq \mathbf{9}, \mathbf{x} \geq \mathbf{0}, \mathbf{y} \geq \mathbf{0}$.

Solution: It is given that: $Z=x+y$ subject to constraints, $x+4 y \leq 8$ $2 x+3 y \leq 12,3 x+y \leq 9, x \geq 0, y \geq 0$ Now construct a constrain table for the above, we have Here, it can be...

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A man rides his motorcycle at the speed of $50 \mathrm{~km} /$ hour. He has to spend Rs 2 per km on petrol. If he rides it at a faster speed of $80 \mathrm{~km} /$ hour, the petrol cost increases to Rs 3 per km. He has at most Rs 120 to spend on petrol and one hour’s time. He wishes to find the maximum distance that he can travel. Express this problem as a linear programming problem.

Solution: Suppose the man covers $\mathrm{x} \mathrm{km}$ on his motorcycle at the speed of $50 \mathrm{~km} / \mathrm{hr}$ and covers $\mathrm{y} \mathrm{km}$ at the speed of $50 \mathrm{~km} /...

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A company manufactures two types of sweaters: type A and type B. It costs Rs 360 to make a type A sweater and Rs 120 to make a tvpe B sweater. The companv can make at most 300 sweaters and spend at most Rs 72000 a day. The number of sweaters of type B cannot exceed the number of sweaters of type A by more than 100 . The company makes a profit of Rs 200 for each sweater of type A and Rs 120 for every sweater of type B. Formulate this problem as a LPP to maximize the profit to the company.

Solution: Suppose $\mathrm{x}$ and $\mathrm{y}$ to be the number of sweaters of type $\mathrm{A}$ and type $\mathrm{B}$ respectively. The following constraints are: $360 x+120 y \leq 72000...

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A company manufactures two types of screws A and B. All the screws have to pass through a threading machine and a slotting machine. A box of Type A screws requires 2 minutes on the threading machine and 3 minutes on the slotting machine. A box of type $B$ screws requires 8 minutes of threading on the threading machine and 2 minutes on the slotting machine. In a week, each machine is available for 60 hours. On selling these screws, the company gets a profit of Rs 100 per box on type A screws and Rs 170 per box on type B screws. Formulate this problem as a LPP given that the objective is to maximize profit.

Solution: Suppose that the company manufactures $\mathrm{x}$ boxes of type A screws and $y$ boxes of type B screws. The below table is constructed from the information provided:...

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A firm has to transport 1200 packages using large vans which can carry 200 packages each and small vans which can take 80 packages each. The cost for engaging each large van is Rs 400 and each small van is Rs 200 . Not more than Rs 3000 is to be spent on the iob and the number of large vans cannot exceed the number of small vans. Formulate this problem as a LPP given that the objective is to minimize cost.

Solution: Suppose $\mathrm{x}$ and $\mathrm{y}$ to be the number of large and small vans respectively. The below constrains table is constructed from the information provided:...

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A manufacturer of electronic circuits has a stock of 200 resistors, 120 transistors and 150 capacitors and is required to produce two types of circuits A and B. Type A requires 20 resistors, 10 transistors and 10 capacitors. Type B requires 10 resistors, 20 transistors and 30 capacitors. If the profit on type A circuit is Rs 50 and that on type B circuit is Rs 60 , formulate this problem as a LPP so that the manufacturer can maximize his profit.

Solution: Suppose $\mathrm{x}$ units of type A and $y$ units of type $\mathrm{B}$ electric circuits be produced by the manufacturer. The table is constructed from the information provided:...

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In the following cases, determine whether the given planes are parallel or perpendicular, and in case they are neither, find the angles between them.
(a) 2x – 2y + 4z + 5 = 0 and 3x – 3y + 6z – 1 = 0
(b) 2x – 2y + 4z + 5 = 0 and 3x – 3y + 6z – 1 = 0

Solution: (a) $2 x-2 y+4 z+5=0$ and $3 x-3 y+6 z-1=0$ It is given that The eq. of the given planes are $2 x-2 y+4 z+5=0$ and $x-2 y+5=0$ It is known to us that, two planes are $\perp$ if the...

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Find the shortest distance between the lines whose vector equations are $\begin{array}{l} \vec{r}=(1-t) \hat{i}+(t-2) \hat{j}+(3-2 t) \hat{k} \text { and } \\ \vec{r}=(s+1) \hat{i}+(2 s-1) \hat{j}-(2 s+1) \hat{k} \end{array}$

Solution: Consider the given equations $\begin{array}{l} \Rightarrow \vec{r}=(1-t) \hat{i}+(t-2) \hat{j}+(3-2 t) \hat{k} \\ \vec{r}=\hat{i}-t \hat{i}+t \hat{j}-2 \hat{j}+3 \hat{k}-2 t \hat{k} \\...

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The general solution of the differential equation \[{{e}^{x}}~dy\text{ }+\text{ }\left( y\text{ }{{e}^{x}}~+\text{ }2x \right)\text{ }dx\text{ }=\text{ }0\text{ }isA.\text{ }x\text{ }ey\text{ }+\text{ }{{x}^{2}}~=\text{ }C\text{ }B.\text{ }x\text{ }ey\text{ }+\text{ }{{y}^{2}}~=\text{ }C\text{ }C.\text{ }y\text{ }ex\text{ }+\text{ }{{x}^{2}}~=\text{ }C\text{ }D.\text{ }y\text{ }ey\text{ }+\text{ }{{x}^{2}}~=\text{ }C\]

Therefore, the correct option is option(c).

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Prove that \[{{\mathbf{x}}^{\mathbf{2}}}~-\text{ }{{\mathbf{y}}^{\mathbf{2}}}~=\text{ }\mathbf{c}\text{ }{{\left( {{\mathbf{x}}^{\mathbf{2}}}~+\text{ }{{\mathbf{y}}^{\mathbf{2}}} \right)}^{\mathbf{2}}}~\] is the general solution of differential equation \[({{\mathbf{x}}^{\mathbf{3}}}-\mathbf{3x}{{\mathbf{y}}^{\mathbf{2}}})\text{ }\mathbf{dx}\text{ }=\text{ }\left( {{\mathbf{y}}^{\mathbf{3}}}-\mathbf{3}{{\mathbf{x}}^{\mathbf{2}}}\mathbf{y} \right)\text{ }\mathbf{dy},\]where c is a parameter.

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Let the vectors \[\overrightarrow{a},\overrightarrow{b},\overrightarrow{c}\] given as \[{{a}_{1}}\widehat{i}+{{a}_{2}}\widehat{j}+{{a}_{3}}\widehat{k}\],\[{{b}_{1}}\widehat{i}+{{b}_{2}}\widehat{j}+{{b}_{3}}\widehat{k}\],\[{{c}_{1}}\widehat{i}+{{c}_{2}}\widehat{j}+{{c}_{3}}\widehat{k}\] . Then show that \[\overrightarrow{a}\times (\overrightarrow{b}+\overrightarrow{c})=\overrightarrow{a}\times \overrightarrow{b}+\overrightarrow{a}\times \overrightarrow{c}\]

It is given that,

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