LFM Pure and Mechanics

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Consider points $P ( x , y )$ on the coordinate plane satisfying the equation $\frac { 2 ^ { x ^ { 2 } } } { 8 } = \frac { 4 ^ { x } } { 2 ^ { y ^ { 2 } } }$. Select the correct options.
(1) When $x = 3$, there are 2 distinct solutions satisfying this equation
(2) If point $( a , b )$ satisfies this equation, then point $( - a , - b )$ also satisfies this equation
(3) All possible points $P ( x , y )$ form a circle
(4) Point $P ( x , y )$ may lie on the line $x + y = 4$
(5) For all possible points $P ( x , y )$, the maximum value of $x - y$ is $1 + 2 \sqrt { 2 }$
taiwan-gsat 2025 Q18 3 marks Applied/Contextual Exponential Modeling View
It is known that UVI values have an exponential relationship with altitude: for every 300-meter increase in altitude, the UVI value increases by 4\% of the value before the increase. At ground level, the ultraviolet radiation received from the sun is 400 joules per square meter. At a mountain 4500 meters above ground level, the UVI value of the ultraviolet radiation received is which of the following options? (Single choice question, 3 points)
(1) $4 ( 1 + 0.04 \times 15 )$
(2) $4 \left( 1 + 0.04 ^ { 15 } \right)$
(3) $4 ( 1 + 0.04 ) ^ { 15 }$
(4) $4 \times 100 ( 1 + 0.04 ) ^ { 15 }$
(5) $4 \times 100 \left( 1 + 0.04 ^ { 45 } \right)$
11. The sum of the roots of the equation $2 ^ { 2 x } - 8 \times 2 ^ { x } + 15 = 0$ is
A 3
B 8
C $\quad 2 \log _ { 10 } 2$
D $\quad \log _ { 10 } \left( \frac { 15 } { 4 } \right)$
E $\quad \frac { \log _ { 10 } 15 } { \log _ { 10 } 2 }$
The graphs of two functions are shown here:
  • $y = a ^ { x }$ is shown with a solid line, where $a$ is a positive real number
  • $y = f ( x )$ is shown with a dashed line

Which of the following statements $( \mathbf { 1 } , \mathbf { 2 } , \mathbf { 3 } , \mathbf { 4 } )$ could be true?
$1 f ( x ) = b ^ { x }$ for some $b > a$
$2 f ( x ) = b ^ { x }$ for some $b < a$
$3 f ( x ) = a ^ { k x }$ for some $k > 1$
$4 f ( x ) = a ^ { k x }$ for some $k < 1$
A $\mathbf { 1 }$ only
B 2 only
C 3 only
D 4 only
E 1 and 3 only
F 1 and 4 only
G 2 and 3 only
H 2 and 4 only
tmua 2017 Q14 1 marks Exponential Equation Solving View
The solution of the simultaneous equations
$$\begin{array} { r } 2 ^ { x } + 3 \times 2 ^ { y } = 3 \\ 2 ^ { 2 x } - 9 \times 2 ^ { 2 y } = 6 \end{array}$$
is $x = p , y = q$.
Find the value of $p - q$
A $\frac { 5 } { 12 }$
B $\frac { 7 } { 3 }$
C $\log _ { 2 } \frac { 5 } { 12 }$
D $\log _ { 2 } \frac { 7 } { 3 }$
E $\log _ { 2 } 9$
F $\quad \log _ { 2 } 15$
Consider the equation $2 ^ { x } = m x + c$, where $m$ and $c$ are real constants.
Which of the following statements is/are true?
I The equation has a negative real solution only if $c > 1$.
II The equation has two distinct real solutions if $c > 1$.
III The equation has two distinct positive real solutions if and only if $c \leq 1$.
tmua 2020 Q5 1 marks MCQ on Function Properties View
Which one of the following shows the graph of
$$y = \frac { 2 ^ { x } } { 1 + 2 ^ { x } }$$
(Dotted lines indicate asymptotes.)
tmua 2020 Q6 1 marks MCQ on Function Properties View
Find the maximum value of the function
$$\mathrm{f}(x) = \frac{1}{5^{2x} - 4(5^x) + 7}$$
A $\frac{1}{7}$
B $\frac{1}{4}$
C $\frac{1}{3}$
D $3$
E $4$
F $7$
tmua 2021 Q4 1 marks MCQ on Function Properties View
Find the minimum value of the function
$$2 ^ { 2 x } - 2 ^ { x + 3 } + 4$$
A - 16 B - 12 C - 8 D 0 E 4 F $\quad 20$
tmua 2021 Q14 1 marks Exponential Equation Solving View
Consider the following simultaneous equations, where $p$ is a real number:
$$\begin{array} { r } p 2 ^ { x } + \log _ { 2 } y = 2 \\ 2 ^ { x } + \log _ { 2 } y = 1 \end{array}$$
What is the complete range of $p$ for which these simultaneous equations have a real solution $( x , y )$ ?
A $p < 1$
B $p \neq 1$
C $p > 1$
D $p < 1$ or $p > 2$
E $\quad p \neq 1$ and $p < 2$ F $p > 1$ and $p < 2$ G $p > 2$ H All real values of $p$
P, Q, R and S show the graphs of
$$y = ( \cos x ) ^ { \cos x } , y = ( \sin x ) ^ { \sin x } , y = ( \cos x ) ^ { \sin x } \text { and } y = ( \sin x ) ^ { \cos x }$$
for $0 < x < \frac { \pi } { 2 }$ in some order.
Which row in the following table correctly identifies the graphs?
$y = ( \cos x ) ^ { \cos x }$$y = ( \sin x ) ^ { \sin x }$$y = ( \cos x ) ^ { \sin x }$$y = ( \sin x ) ^ { \cos x }$
APQRS
BPQSR
CQPRS
DQPSR
ERSPQ
FRSQP
GSRPQ
HSRQP
Consider the claim: For all positive real numbers $x$ and $y$,
$$\sqrt { x ^ { y } } = x ^ { \sqrt { y } }$$
Which of the following is/are a counterexample to the claim? I $x = 1 , y = 16$ II $x = 2 , y = 8$ III $x = 3 , y = 4$
A none of them B I only C II only D III only E I and II only F I and III only G II and III only H I, II and III
tmua 2023 Q7 1 marks Exponential Equation Solving View
$\mathrm { P } ( x )$ and $Q ( x )$ are defined as follows:
$$\begin{aligned} & \mathrm { P } ( x ) = 2 ^ { x } + 4 \\ & \mathrm { Q } ( x ) = 2 ^ { ( 2 x - 2 ) } - 2 ^ { ( x + 2 ) } + 16 \end{aligned}$$
Find the largest value of $x$ such that $\mathrm { P } ( x )$ and $Q ( x )$ are in the ratio $4 : 1$, respectively.
tmua 2023 Q15 1 marks Parameter Determination from Conditions View
The difference between the maximum and minimum values of the function $f ( x ) = a ^ { \cos x }$, where $a > 0$ and $x$ is real, is 3 .
Find the sum of the possible values of $a$.
$12^{a} = 2$
$$6^{b} = 3$$
Given that, what is the value of the expression $\mathbf{12}^{\boldsymbol{(}\mathbf{1} - \mathbf{a}\mathbf{)2b}}$?
A) 15 B) 16 C) 9 D) 8 E) 4
turkey-yks 2011 Q9 Solve a Logarithmic Equation View
$$\frac{2^{x^{2} - y^{2}}}{4^{x^{2} + xy}} = \frac{1}{2}$$
Given that, what is the value of the expression $(x + y)^{2}$?
A) 2 B) 4 C) 1 D) $\frac{1}{2}$ E) $\frac{1}{4}$
$$2 ^ { 2 x } - 2 \cdot 2 ^ { x } - 8 = 0$$
Given this equation, which of the following is x?
A) 2
B) 1
C) $\ln 2$
D) $\ln 4$
E) $2 \ln 4$
turkey-yks 2012 Q8 Exponential Equation Solving View
Let x be a real number such that
$$( \sqrt { 7 } + \sqrt { 3 } ) ^ { x } = 4$$
Given this, which of the following is the expression $( \sqrt { 7 } - \sqrt { 3 } ) ^ { x }$ equal to?
A) $2 ^ { - x }$
B) $2 ^ { - x + 1 }$
C) $4 ^ { x }$
D) $4 ^ { x - 1 }$
E) $4 ^ { x + 1 }$
turkey-yks 2013 Q39 Modular Arithmetic Computation View
$$\lim _ { x \rightarrow \infty } \frac { e ^ { - 3 x } + e ^ { 2 x } } { \ln x + 3 e ^ { 2 x } }$$
What is the value of this limit?
A) $\frac { 1 } { 2 }$
B) $\frac { 3 } { 2 }$
C) $\frac { 1 } { 3 }$
D) 0
E) 1
turkey-yks 2014 Q4 Solve a Logarithmic Equation View
$\mathbf { x }$ is a real number and
$$\left( \frac { 1 } { 6 } \right) ^ { x } = \left( \frac { 4 } { 3 } \right) ^ { x + 1 }$$
Given this, what is $8 ^ { \mathbf { X } }$?
A) $\frac { 2 } { 3 }$
B) $\frac { 3 } { 4 }$
C) $\frac { 1 } { 8 }$
D) $\frac { 3 } { 8 }$
E) $\frac { 2 } { 9 }$
A function f is defined on the set of real numbers as
$$f ( x ) = 1 + e ^ { - x }$$
Accordingly, I. The range of function f is $( 1 , \infty )$. II. Function f is decreasing on its domain. III. The line $y = 0$ is a horizontal asymptote of function f. Which of the following statements are true?
A) Only II
B) Only III
C) I and II
turkey-yks 2017 Q8 Exponential Equation Solving View
$$\begin{aligned} & 4 ^ { x } + 4 ^ { y } = 10 \\ & 4 ^ { x } - 4 ^ { y } = 8 \end{aligned}$$
Accordingly, what is the value of the expression $\mathbf { 2 } ^ { \mathbf { x } + \mathbf { y } }$?
A) 2 B) 3 C) 4 D) 5 E) 6