LFM Pure and Mechanics

View all 505 questions →

tmua 2019 Q14 1 marks View
Consider the following statements about the polynomial $\mathrm { p } ( x )$, where $a < b$ :
I $\quad \mathrm { p } ( a ) \leq \mathrm { p } ( b )$
II $\quad \mathrm { p } ^ { \prime } ( a ) \leq \mathrm { p } ^ { \prime } ( b )$
III $\mathrm { p } ^ { \prime \prime } ( a ) \leq \mathrm { p } ^ { \prime \prime } ( b )$
Which of these statements is a necessary condition for $\mathrm { p } ( x )$ to be increasing for $a \leq x \leq b$ ?
Find the shortest distance between the curve $y = x^2 + 4$ and the line $y = 2x - 2$.
The function f is defined for all real $x$ as
$$\mathrm{f}(x) = (p-x)(x+2)$$
Find the complete set of values of $p$ for which the maximum value of $\mathrm{f}(x)$ is less than 4.
A $-2 - 4\sqrt{2} < p < -2 + 4\sqrt{2}$
B $-2 - 2\sqrt{2} < p < -2 + 2\sqrt{2}$
C $-2\sqrt{5} < p < 2\sqrt{5}$
D $-6 < p < 2$
E $-4 < p < 0$
F $-2 < p < 2$
The function f is given by
$$\mathrm { f } ( x ) = x ^ { \frac { 1 } { 7 } } \left( x ^ { 2 } - x + 1 \right)$$
Find the fraction of the interval $0 < x < 1$ for which $\mathrm { f } ( x )$ is decreasing.
A $\frac { 2 } { 15 }$
B $\frac { 1 } { 5 }$
C $\frac { 1 } { 3 }$
D $\frac { 1 } { 2 }$
E $\frac { 2 } { 3 }$
F $\frac { 4 } { 5 }$
G $\frac { 13 } { 15 }$
The minimum value of the function $x ^ { 4 } - p ^ { 2 } x ^ { 2 }$ is - 9 $p$ is a real number.
Find the minimum value of the function $x ^ { 2 } - p x + 6$
A - 3 B $6 - \frac { 3 \sqrt { 2 } } { 2 }$ C $\frac { 3 } { 2 }$ D 3 E $\frac { 9 } { 2 }$ F $6 + \frac { 3 \sqrt { 2 } } { 2 }$
Determine the number of stationary points on the curve with equation
$$y = 3 x ^ { 4 } + 4 x ^ { 3 } + 6 x ^ { 2 } - 5$$
A 0
B 1
C 2
D 3
E 4
Given that
$$\left( a ^ { 3 } + \frac { 2 } { b ^ { 3 } } \right) \left( \frac { 2 } { a ^ { 3 } } - b ^ { 3 } \right) = \sqrt { 2 }$$
where $a$ and $b$ are real numbers, what is the least value of $a b$ ?
The following shape has two lines of reflectional symmetry.
$M N O P$ is a square of perimeter 40 cm .
The vertices of rectangle $R S T U$ lie on the edge of square $M N O P$.
$M R$ has length $x \mathrm {~cm}$.
What is the largest possible value of $x$ such that $R S T U$ has area $20 \mathrm {~cm} ^ { 2 }$ ?
The function
$$f ( x ) = \frac { 2 } { 3 } x ^ { 3 } + 2 m x ^ { 2 } + n , \quad m > 0$$
has three distinct real roots.
What is the complete range of possible values of $n$, in terms of $m$ ?
The diagram shows the graph of $y = f ( x )$
The function $f$ attains its maximum value of 2 at $x = 1$, and its minimum value of - 2 at $x = - 1$
Find the difference between the maximum and minimum values of $( f ( x ) ) ^ { 2 } - f ( x )$
3

For real numbers $t$ satisfying $-1 \leq t \leq 1$, let $$x(t) = (1+t)\sqrt{1+t}, \quad y(t) = 3(1+t)\sqrt{1-t}$$ Consider the point $\mathrm{P}(x(t),\ y(t))$ in the coordinate plane.

(1) Show that the function $\dfrac{y(t)}{x(t)}$ of $t$ on $-1 < t \leq 1$ is strictly decreasing.

(2) Let $f(t)$ be the distance from the origin to $\mathrm{P}$. Investigate the monotonicity of the function $f(t)$ of $t$ on $-1 \leq t \leq 1$, and find its maximum value.

(3) Let $C$ be the locus of $\mathrm{P}$ as $t$ ranges over $-1 \leq t \leq 1$, and let $D$ be the region enclosed by $C$ and the $x$-axis. When $D$ is rotated $90°$ clockwise about the origin, find the area of the region swept out by $D$.
%% Page 4
5

Let $\alpha$ be a positive real number. Define the function $f(\theta)$ of $\theta$ for $0 \leq \theta \leq \pi$ as the square of the distance AP between the two points $\mathrm{A}(-\alpha,\ -3)$ and $\mathrm{P}(\theta + \sin\theta,\ \cos\theta)$ in the coordinate plane.
  1. [(1)] Show that there exists exactly one $\theta$ in the range $0 < \theta < \pi$ such that $f'(\theta) = 0$.
  2. [(2)] Find the range of $\alpha$ such that the following holds: [6pt] The function $f(\theta)$ of $\theta$ for $0 \leq \theta \leq \pi$ attains its maximum at some point in the interval $0 < \theta < \dfrac{\pi}{2}$.

%% Page 6
1

Consider the following function $f(x)$.
$$f(x) = (\cos x)\log(\cos x) - \cos x + \int_0^x (\cos t)\log(\cos t)\, dt \quad \left(0 \leq x < \frac{\pi}{2}\right)$$
  • [(1)] Show that $f(x)$ has a minimum value on the interval $0 \leq x < \dfrac{\pi}{2}$.
  • [(2)] Find the minimum value of $f(x)$ on the interval $0 \leq x < \dfrac{\pi}{2}$.

%% Page 2
2

Consider the following function $f(x)$. $\displaystyle f(x) = \int_0^1 \frac{|t-x|}{1+t^2}\,dt \quad (0 \leq x \leq 1)$

(1) Find all real numbers $\alpha$ satisfying $0 < \alpha < \dfrac{\pi}{4}$ such that $f'(\tan\alpha) = 0$.

(2) For the value of $\alpha$ found in (1), find the value of $\tan\alpha$.

(3) Find the maximum value and the minimum value of $f(x)$ on the interval $0 \leq x \leq 1$. If necessary, you may use the fact that $0.69 < \log 2 < 0.7$.
%% Page 3
$$f(x) = x^{4} - 5x^{2} + 4$$
What is the maximum value of the function on the interval $\left[\frac{-1}{2}, \frac{1}{2}\right]$?
A) 8
B) 6
C) 4
D) 2
E) 0
For points $(x, y)$ on the boundary of the bounded region between the parabola $y = x ^ { 2 }$ and the line $y = 2 - x$, what is the maximum value of the expression $\mathbf { x } ^ { \mathbf { 2 } } + \mathbf { y } ^ { \mathbf { 2 } }$?
A) 25
B) 20
C) 17
D) 13
E) 10
Below is the graph of the derivative of a function f defined on the interval $[ - 5,5 ]$.
According to this graph, I. The function f is decreasing for $x > 0$. II. $f ( - 2 ) > f ( 0 ) > f ( 2 )$. III. The function f has local extrema at $x = - 2$ and $x = 2$. Which of the following statements are true?
A) Only I
B) Only II
C) I and II
D) I and III
E) I, II and III
A third-degree real-coefficient polynomial function $P(x)$ with leading coefficient 1 has two of its roots as $-5$ and $2$.
If $P(x)$ has a local extremum at the point $x = 0$, what is the third root?
A) $\frac { 1 } { 2 }$
B) $\frac { 3 } { 2 }$
C) $\frac { 7 } { 3 }$
D) $\frac { -5 } { 2 }$
E) $\frac { -10 } { 3 }$
Below, the graph of the derivative of a function f that is defined and continuous on the set of real numbers is given.
Accordingly,
I. $f ( 2 ) - f ( 1 ) = -2$. II. The function f has a local maximum at the point $x = 0$. III. The second derivative function is defined at the point $x = 0$.
Which of the following statements are true?
A) Only I
B) Only III
C) I and II
D) II and III
E) I, II and III
A tour company charges 140 TL per person for a tour it will organize. If the number of registered participants exceeds 80, a refund of 50 kuruş will be made to all participants for each person above 80. The capacity is limited to 200 people.
For example, if 100 people participate in the tour, everyone receives a 10 TL refund and the per-person fee is 130 TL.
Accordingly, how many people should participate in the tour so that the company's revenue from participants is maximum?
A) 160
B) 165
C) 175
D) 180
E) 185
The graph of the derivative function $f ^ { \prime }$ of a function f defined on the set of real numbers is given below.
Accordingly, regarding the function f: I. It is decreasing. II. $f ( a )$ is a local maximum value. III. $f ^ { \prime \prime } ( a )$ is not defined.
Which of the following statements are true?
A) Only I
B) Only II
C) I and III
D) II and III
E) I, II and III
Let $f$ be a function defined on the set of real numbers, and let the derivative of $f$ be denoted by $f ^ { \prime }$. The graph of the function $f ^ { \prime }$ is the parabolic curve shown in the figure.
Accordingly, regarding the function f: I. $f ( 0 ) < 0$ II. It is decreasing on the interval (-a, a). III. $f ( a )$ is a local minimum value.
Which of the following statements are definitely true?
A) Only II
B) Only III
C) I and II
D) II and III
E) I, II and III
The graph of the derivative function $f ^ { \prime }$ of a function f defined on the set of real numbers is given in the following Cartesian coordinate plane.
Accordingly; what is the correct ordering of the values $\mathbf { f } ( \mathbf { 0 } )$, $\mathbf { f } ( \mathbf { 1 } )$ and $\mathbf { f } ( \mathbf { 2 } )$?
A) $\mathrm { f } ( 0 ) < \mathrm { f } ( 1 ) < \mathrm { f } ( 2 )$ B) $\mathrm { f } ( 0 ) < \mathrm { f } ( 2 ) < \mathrm { f } ( 1 )$ C) $f ( 1 ) < f ( 2 ) < f ( 0 )$ D) $\mathrm { f } ( 2 ) < \mathrm { f } ( 0 ) < \mathrm { f } ( 1 )$ E) $\mathrm { f } ( 2 ) < \mathrm { f } ( 1 ) < \mathrm { f } ( 0 )$
A function f is defined on the set of real numbers as
$$f ( x ) = x ^ { 2 } + x - 4$$
A function g defined and continuous on the set of real numbers has a derivative $g ^ { \prime }$ such that $g ^ { \prime } ( x ) = 0$ only for $x = 2$. Accordingly, the product of the x values satisfying
$$( g \circ f ) ^ { \prime } ( x ) = 0$$
is what?
A) 0
B) 1
C) 3
D) 4
E) 6
A function f is continuous on the closed interval $[ 0,6 ]$ and differentiable on each of the open intervals $( 0,3 ) , ( 3,4 ) , ( 4,6 )$. The graph of its derivative $f ^ { \prime }$ is given in the rectangular coordinate plane below.
$$\begin{gathered} \text{Let } 0 < c < 2 \text{ and } \\ f ( 0 ) = 5 \end{gathered}$$
Accordingly, which of the following could be the value of f(6)?
A) 5,5
B) 7,3
C) 10,1
D) 12,7
E) 14,9