12th Standard CBSE Maths Application Of Derivatives Important Quetions
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12th Standard CBSE Maths Application Of Derivatives Important Quetions
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Application Of Derivatives
12th Standard CBSE
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Reg.No. :
Maths
Part-A
use only black and blue ink to write and pencil to draw
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If P(A) = \(\frac12\), P(B) = 0, then P(A|B) is ______.
(a)0
(b)\(\frac12\)
(c)not defined
(d)1
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Let f : R ➝ R be defined as f (x) = 3x. Choose the correct answer
(a)f is one-one onto
(b)f is many-one onto
(c)f is one-one but not onto
(d)f is neither one-one nor onto
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Consider a binary operation * on N defined as a * b = a3 + b3. Choose the correct answer
(a)Is * both associative and commutative?
(b)Is * commutative but not associative?
(c)Is * associative but not commutative?
(d)Is * neither commutative nor associative?
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If A = {1,3,5,7} and define a relation, such that R = { (a,b) a,b ∈ A : |a+b| = 8}. Then how many elements are there in the relation R
(a)8
(b)16
(c)1
(d)4
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If A = diag(3, -1), then matrix A is
(a)\(\begin{bmatrix} 0 & 3 \\ 0 & -1 \end{bmatrix}\)
(b)\(\begin{bmatrix} -1 & 0 \\ 3 & 0 \end{bmatrix}\)
(c)\(\begin{bmatrix} 3 & 0 \\ 0 & -1 \end{bmatrix}\)
(d)\(\begin{bmatrix} 3 & -1 \\ 0 & 0 \end{bmatrix}\)
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The number of all possible matrices of order 3 × 3 with each entry
(a)27
(b)18
(c)81
(d)512
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If A, B are symmetric matrices of same order, then AB – BA is a
(a)Skew symmetric matrix
(b)Symmetric matrix
(c)Zero matrix
(d)Identity matrix
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For what real value of y will matrix A be equal to matrix B, where
\(A=\begin{bmatrix} 3x-4 & 5y \\ 8 & { y }^{ 2 }-4y \end{bmatrix};B=\begin{bmatrix} x+1 & 6{ y }^{ 2 }+1 \\ 8 & -3 \end{bmatrix}\)(a)1, 3
(b)No real value
(c)1/3, 1/2
(d)2 and 3
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A function \(f(x)=\begin{cases} \frac { sinx }{ x } +cosx,x\neq 0 \\ 2k\quad \quad \quad \quad ,x=0 \end{cases}\) is continuous at x = 0 for
(a)k = 1
(b)k = 2
(c)K = \(\frac12\)
(d)k = \(\frac32\)
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If y = tan-1 \(\left( \frac { 1-{ x }^{ 2 } }{ 1+{ x }^{ 2 } } \right) \), then \(\frac { dy }{ dx } \) is equal to
(a)\(\frac { 1 }{ 1+{ x }^{ 4 } } \)
(b)\(\frac { -2x }{ 1+{ x }^{ 4 } } \)
(c)\(\frac { -1 }{ 1+{ x }^{ 4 } } \)
(d)\(\frac { { x }^{ 2 } }{ 1+{ x }^{ 4 } } \)
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The equation of the normal to the curve y = sin x at (0, 0) is
(a)x = 0
(b)y = 0
(c)x + y = 0
(d)x – y = 0
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The absolute maximum value of y = x3 – 3x + 2 in 0 ≤ x ≤ 2 is
(a)4
(b)6
(c)2
(d)0
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The interval in which y = x2 e–x is increasing is
(a)(– ∞, ∞)
(b)(– 2, 0)
(c)(2, ∞)
(d)(0, 2)
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For all real values of x, the minimum value of \(\frac { 1-x+{ x }^{ 2 } }{ 1+x+{ x }^{ 2 } } \) is
(a)0
(b)1
(c)3
(d)\(\frac { 1 }{ 3 } \)
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Let \({ I }_{ 1 }=\int _{ 1 }^{ 2 }{ \frac { dx }{ \sqrt { 1+{ x }^{ 2 } } } } \) and \({ I }_{ 2 }=\int _{ 1 }^{ 2 }{ \frac { dx }{ x } } \), then
(a)I1 > I2
(b)I2 > I1
(c)I1 = I2
(d)I1 > 2I2
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\(\int { \sqrt { { x }^{ 2 }-8x+7 } } dx\) is equal to
(a)\(\frac { 1 }{ 2 } (x-4)\sqrt { { x }^{ 2 }-8x+7 } + 9log|x-4+\sqrt { { x }^{ 2 }-8x+7 } |+\)C
(b)\(\frac { 1 }{ 2 } (x+4)\sqrt { { x }^{ 2 }-8x+7 } + 9log|x+4+\sqrt { { x }^{ 2 }-8x+7 } |+\)C
(c)\(\frac { 1 }{ 2 } (x-4)\sqrt { { x }^{ 2 }-8x+7 } - 3\sqrt2log|x-4+\sqrt { { x }^{ 2 }-8x+7 } |+\)C
(d)\(\frac { 1 }{ 2 } (x-4)\sqrt { { x }^{ 2 }-8x+7 } - \frac92log|x-4+\sqrt { { x }^{ 2 }-8x+7 } |+\)C
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Area of a rectangle having vertices A, B, C and D with position vectors \(-\widehat { i } +\frac { 1 }{ 2 } \widehat { j } +4\widehat { k } \), \(\widehat { i } +\frac { 1 }{ 2 } \widehat { j } +4\widehat { k } \), \(\widehat { i } -\frac { 1 }{ 2 } \widehat { j } +4\widehat { k } \) and \(-\widehat { i } -\frac { 1 }{ 2 } \widehat { j } +4\widehat { k } \), respectively is
(a)\(\frac12\)
(b)1
(c)2
(d)4
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If a, b, c and d are the position vectors of the points A, B, C and D such that a + c = b + d, then ABCD is a
(a)Trapezium
(b)Rectangle
(c)Square
(d)Parallelogram
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The probability of obtaining an even prime number on each die, when a pair of dice is rolled is _____.
(a)0
(b)\(\frac13\)
(c)\(\frac{1}{12}\)
(d)\(\frac{1}{36}\)
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Suppose that two cards are drawn at random from a deck of cards. Let X be the number of aces obtained. Then the value of E(X) is
(a)\(\frac{37}{221}\)
(b)\(\frac{5}{13}\)
(c)\(\frac{1}{13}\)
(d)\(\frac{2}{13}\)
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If f(x) = 27x3 and g(x) = x1/3 find gof(x).
(a)\(gof(x)=g\left( f\left( x \right) \right) =g\left( 27{ x }^{ 3 } \right) ={ \left( 27{ x }^{ 3 } \right) }^{ 1/3 }=3x\)
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If \(2\begin{bmatrix} 1 & 3 \\ 0 & x \end{bmatrix}+\begin{bmatrix} y & 0 \\ 1 & 2 \end{bmatrix}=\begin{bmatrix} 5 & 6 \\ 1 & 8 \end{bmatrix}\), then write the value of (x+y).
(a)\(\begin{bmatrix} 2 & 6 \\ 0 & 2x \end{bmatrix}+\begin{bmatrix} y & 0 \\ 1 & 2 \end{bmatrix}=\begin{bmatrix} 5 & 6 \\ 1 & 8 \end{bmatrix}\)
\(\Rightarrow \begin{bmatrix} 2+y & 6 \\ 1 & 2x+2 \end{bmatrix}=\begin{bmatrix} 5 & 6 \\ 1 & 8 \end{bmatrix}\)
\(\Rightarrow 2+y=5,2x+2=8\Rightarrow x=3,y=3\)
\(\therefore \ x+y=3+3=6\) -
If the following matrix is skew symmetric, find the values of a, b, c
\(A=\left[ \begin{matrix} 0 & a & 3 \\ 2 & b & -1 \\ c & 1 & 0 \end{matrix} \right] \)(a)a = -2, b = 0, c = -3
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Show that the function f (x) = \(\begin{cases} { x }^{ 3 }+3\quad ,\quad if\quad x\neq 0 \\ 1\quad \quad \quad ,\quad if\quad x=0 \end{cases}\) is not continuous at x = 0.
(a)\(\lim _{ x\rightarrow 0 }{ f(x) } =\lim _{ x\rightarrow 0 }{ \left( { x }^{ 3 }+3 \right) } =0+3=3\)
\(f(0)=1\)
\(Thus\quad \lim _{ x\rightarrow 0 }{ f(x) } \neq f(0)\)
\(Hence,\quad f\quad is\quad not\quad continuous\quad at\quad x=0.\)
3\(\neq \)f (0), discontinuous. -
The total cost C(x) in Rupees, associated with the production of x units of an item is given by
C(x) = 0.005 x3 – 0.02 x2 + 30x + 5000
Find the marginal cost when 3 units are produced, where by marginal cost we mean the instantaneous rate of change of total cost at any level of output.(a)Since marginal cost is the rate of change of total cost with respect to the output, we have
Marginal \(\operatorname{cost}(\mathrm{MC})=\frac{d C}{d x}=0.005\left(3 x^{2}\right)-0.02(2 x)+30\)
When x = 3, MC =0.015(32 ) − 0.04(3) + 30
= 0.135 – 0.12 + 30 = 30.015
Hence, the required marginal cost is Rs. 30.02 (nearly). -
Evaluate the integral: \(({\int{\sqrt x+{1\over\sqrt x}}})^2dx.\)
(a)Consider : \(\int({\sqrt x+{1\over \sqrt x}})^2dx=\int({x+{1\over x+2}+2})dx={x^2\over2}+log |x| + 2x + c\)
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\(\int {1+tan\ x\over 1-tan\ x}dx\).
(a)\(\int \frac{1+\tan x}{1-\tan x} d x =\int \frac{\cos x+\sin x}{\cos x-\sin x} d x \)
\(=-\int \frac{1}{t} d t \)
\(=-\log |t|+C \)
\(=-\log |\cos x-\sin x|+C\) -
\(\int tan^{-1}(cot\ x)dx.\)
(a)\(\text { We have }\int \tan ^{-1}(\cot x) d x=\int \tan ^{-1}\left\{\tan \left(\frac{\pi}{2}-x\right)\right\} d x=\int\left(\frac{\pi}{2}-x\right) d x=\frac{\pi}{2} x-\frac{x^{2}}{2}+C \)
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What is the cosine of the angle which the vector \(\sqrt { 2 } \hat { i } +\hat { j } +\hat { k } \) makes with y-axis?
(a)\(\text { Let } \vec{a}=\sqrt{2} \hat{i}+\hat{j}+\hat{k} \)
\(\text { then } \hat{a}=\frac{1}{\sqrt{2}} \hat{i}+\frac{1}{2} \hat{j}+\frac{1}{2} \hat{k} \)
\(\text { Cosine of an angle with } y \text { -axis is coefficient of } \hat{j} \text { , }\)
\(cos\beta =\frac { 1 }{ 2 } \) -
Find the scalar components of the vector \(\overset\rightarrow {AB} \) with initial point A(2, 1) and terminal point B(-5, 7).
(a)\(\overset\rightarrow {AB}\) = Position vector of B-Position vector of A
\(=(-5\overset\wedge i+7\overset\wedge j)-(2\overset\wedge i+1\overset\wedge j)\)
\(=(-5-2)\overset\wedge i+(7-1)\overset\wedge j\)
\(=-7\overset\wedge i+6\overset\wedge j\)
\(\therefore\) The scalar components are (-7,6,0). -
Find \(\lambda\) and \(\mu\) if \((\overset\wedge i+3\overset\wedge j+9\overset\wedge k)\times(3\overset\wedge i-\lambda \overset\wedge j+\mu \overset\wedge k)=0\)
(a)Getting \(\lambda =-9\)
and \(\mu=27\)
Alternative Method :
\((\overset\wedge i+3\overset\wedge j+9\overset\wedge k)\times(3\overset\wedge i-\lambda \overset\wedge j+\mu\overset\wedge k)=0\)
\(\Rightarrow \left| \begin{matrix} \overset { \wedge }{ i } & \overset { \wedge }{ j } & \overset { \wedge }{ k } \\ 1 & 3 & 9 \\ 3 & -\lambda & \mu \end{matrix} \right| \)
\(\Rightarrow \overset\wedge i(3\mu+9\lambda)-\overset\wedge j(\mu-27)+\overset\wedge k(-\lambda-9)=0\)
\(\Rightarrow 3\mu+9\lambda=0 ....(i)\)
\(\Rightarrow \mu-27=0 ...(ii)\)
\(\Rightarrow -\lambda-9=0...(iii)\)
from eqn.(ii) and (iii),
\(\mu=27\)
and \(\lambda=-9\) -
Given P(A) = 0.4, P(B) = 0.7 and P(B/A) = 0.6, Find \(P(A\cup B)\)
(a)\(P(B / A) =\frac{P(A \cap B)}{P(A)} \)
\(\Rightarrow 0.6 \times 0.4 =P(A \cap B)\)
\(\Rightarrow P(A \cap B) =0.24 \)
\(\text { Now, } \ P(A \cup B) =P(A)+P(B)-P(A \cap B) \)
\(=0.4+0.7-0.24=0.86 \) -
Let f and g be real function be \(f(x)=\sqrt { x+4 } ,x\ge 4\) find the function fg, \(\frac { f }{ g } \)
(a) -
Find the value of X and Y if
\(X+Y=\left[ \begin{matrix} 2 & 3 \\ 5 & 1 \end{matrix} \right] ,X-Y=\left[ \begin{matrix} 6 & 5 \\ 7 & 3 \end{matrix} \right] \)(a) -
Find the value of x and y in each if AB exist
(i) \({ A }_{ 3\times x },{ B }_{ 4\times y }\) and \({ AB }_{ 3\times 3 }\)
(ii) \({ A }_{ x\times 2 },{ B }_{ y\times 4 }\) and \({ AB }_{ 3\times 4 }\)(a) -
If y = tan-1\(\sqrt { \frac { 1-x }{ 1+x } } find\frac { dy }{ dx } \)
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If x = \(\frac { at }{ 1+{ t }^{ 2 } } ,y=\frac { a{ t }^{ 2 } }{ 1+{ t }^{ 2 } } ,find\frac { dy }{ dx } at\) t = 2
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Find the point on the curve \(y^2 =8x + 3\) for which the y-coordinate changes 4 times more than coordinate of x.
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\(\int { { sin }^{ 2 }x{ \ cos }^{ 2 }x } dx\)
(a) -
Find the unit vector in the direction of \(\overset\rightarrow a+\overset\rightarrow b\)if \(\overset\rightarrow a= 2\overset\wedge i+\overset\wedge j+3\overset\wedge k\), and \(\overset\rightarrow b= \overset\wedge i+2\overset\wedge j-\overset\wedge k\)
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If P(E) = \(\frac { 7 }{ 13 } \) , P(F) = \(\frac { 9 }{ 13 } \) and P(E\(\cap\)F) = \(\frac { 4 }{ 13 } \),then evaluate :
(a) \(P(\overline { E } /F)\)
(b) \(P(\overline { E } /F)\)(a) -
Show that the relation R in the set Z of integers given by:
R = {(a, b) : 2 divides a-b} is an equivalence relation(a) -
(Diet Problem) A dietician has to develop a special diet using two foods P and Q. Each packet (containing 50g) of food P contains 12 units of calcium, 4 units of iron, 6 units of cholesterol and 6 units of vitamin A. Each packet of the same quantity of food q contains 3 units of calcium, 20 units of iron, 4 units of cholesterol and 3 units of vitamin A. The diet requires at least 240 units of calcium, at least 460 units of iron and at most 300 units of cholesterol. How many packets of each food should be used to minimise the amount of vitamin A in the diet. What is the minimum amount of vitamin A?
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In each of the following cases, state whether the function is one-one, onto or bijective. Justify your answer.
(i) \(f:R\rightarrow R\) defined by f(x) = 3 - 4x
(ii) \(f:R\rightarrow R\) defined by \(f(x)=1+x^{ 2 }\) .(a) -
Find X, if \(Y=\begin{bmatrix} 3 & 2 \\ 1 & 4 \end{bmatrix}\) and \(2X+Y=\begin{bmatrix} 1 & 0 \\ -3 & 2 \end{bmatrix}\) .
(a) -
Discuss the continuity of the function f given by f(x) = | x | at x = 0.
(a) -
Discuss the continuity of the function f defined by:
\(f(x)={ x }^{ 3 }+{ x }^{ 2 }-1\)(a) -
Differentiate \({ tan }^{ -1 }\left( \frac { \sqrt { 1+{ x }^{ 2 } } -1 }{ x } \right) \) w.r.t.x.
(a) -
Prove that the function given by by f (x) = cos x is
(a) strictly decreasing in \((0,\pi )\)
(b) strictly increasing in \((\pi ,2\pi )\)
(c) neither increasing nor decreasing in \((0,2\pi )\)(a) -
Find the absolute maximum and absolute value of the function given by:
\(f(x)sin^{ 2 }x-cosx,x\in [0,\pi ]\)(a) -
Let \(\vec{a}=\hat{i}+2 \hat{j} \text { and } \vec{b}=2 \hat{i}+\hat{j} . \text { Is }|\vec{a}|=|\vec{b}| ?\) Are the vector \(\overset { \rightarrow }{ a } \) is \(\overset { \rightarrow }{ b } \) equal?
(a) -
Six balls are drawn successively from an urn containing 7 red and 9 black balls.Tell whether or not the trials of drawing black balls are Bernoulli trials when after each draws the ball drawn is:
(i) replaced
(ii) not replaced in the urn.(a) -
Two numbers are selected at random (without replacement)from first six positive integers 2, 3, 4, 5, 6 and 7. Let X denote the larger of the two numbers obtained. Find the probability distribution of X. Find the mean and variance of this distribution
(a) -
Show that the relation S in the set R of real numbers, defined as
S = {(a, b): a,b \(\in\)R and a \(\le\)b3} is neither reflexive, nor symmetric nor transitive.(a) -
Check the injectivity and surjectivity of the following
(i) f : N \(\rightarrow\) N given by f(x) = x2
(ii) f : R \(\rightarrow\) R given by f(x) = x2
(iii) f : Z → Z given by f(x) = x2
(iv) f : N → N given by f(x) = x3
(v) f : Z → Z given by f(x) = x3(a) -
Using elementary transformations, find the inverse of the matrix
\(\left[ \begin{matrix} 1 & 3 & -2 \\ -3 & 0 & -1 \\ 2 & 1 & 0 \end{matrix} \right] \).
(a) -
Find the value of a for which the function f defined by
\(f(x)=\begin{cases} a\quad sin\frac { \pi }{ 2 } (x+1)\quad \quad ,\quad x\le 0 \\ \frac { tan\quad x\quad -\quad sin\quad x }{ { x }^{ 3 } } \ \ \ \ ,\quad x>0 \end{cases}\) is continuous at x = 0.
(a) -
Let f be a function defined on an open interval I.(First Derivative Test)
(a) -
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Check whether the function:
\(f(x)=x^{ 100 }+sinx-1\)
is strictly increasing or strictly decreasing or none of both on(-1,1). Should the nature of a man be like this function? Justify your answer.(a) -
Evaluate the integral: \(\int sin\ x.\ sin2x.\ sin3x\ dx\)
(a)
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Evaluate: \(\int _{ 0 }^{ \pi /2 }{ \frac { x\sin { x\cos { x } } }{ \sin ^{ 4 }{ x } +\cos ^{ 4 }{ x } } } dx.\)
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Points L,M,N divide the sides BC,CA and AB of a triangle ABC in the ratio 1:4,3:2 and 3:7 respectively. Prove that \(\overrightarrow { AL } +\overrightarrow { BM } +\overrightarrow { CN } \) is a vector parallel to \(\overrightarrow { CK } \) where k divides AB in the ratio 1:3
(a)
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In a factory which manufactures bolts, machines A, B and C manufacture respectively 25%, 35% and 40% of the bolts. Of their outputs, 5, 4 and 2 percent are respectively defective bolts. A bolt is drawn at random from the product and is found to be defective. What is the probability that it is manufactured by the machine B?
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Show that the function \(f:R \rightarrow \{x\in R:-1 < x < 1\}\)
defined by \(f(x)=\frac { x }{ 1+|x|^{ ' } } ,x\in R\) is one-one and onto function. (a)
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Using elementary transformation, find the inverse of the matrix \(A=\left[ \begin{matrix} 8 & 4 & 3 \\ 2 & 1 & 1 \\ 1 & 2 & 2 \end{matrix} \right] \) and use it to solve the following system of lines equations :
8x + 4y + 3z = 19
2x + y + z = 5
x + 2y + 2z = 7(a) -
The sum of three numbers is -1. If we multiply the second number by 2 , third number by 3 and add them we get 5. If we subtract the third number from the sum of first and second numbers we get -1. Represent it by a system of equations . Find the three numbers using inverse of a matrix
(a)
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Find the point P on the curve \(y^2= 4ax\) which is nearest to the point (11a, 0).
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Find : \(\int { \frac { \sqrt { x^{ 2 }+1 } \left\{ log({ x }^{ 2 }+1)-2logx \right\} }{ x^{ 4 } } } dx\)
(a)
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A man is known to speak the truth 3 out of 5 times. He throws a die and reports that it is 1. Find the probability that it is actually 1.
(a)
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