# Recent questions tagged functions

1
Answer the questions on the basis of the information given below: $f_{1}(x) = \left\{\begin{matrix} x & 0 \leq x \leq 1 \\ 1 & x \geq 1 \\ 0 & \text{otherwise} \end{matrix}\right.$ $f_{2}(x) = f_{1}(-x) \;\; \text{for all} \; x$ ... $f_2(-x) = f_4(x) \: \text{for all }\;x$ $f_1(x) + f_3(x) = 0 \: \text{for all }\;x$
1 vote
2
If $f(x) = x^{2} – 7x$ and $g(x) = x + 3,$ then the minimum value of $f(g(x)) – 3x$ is $-16$ $-15$ $-20$ $-12$
1 vote
3
For all real values of $x,$ the range of the function $f(x) = \dfrac{x^{2} + 2x + 4}{2x^{2} + 4x + 9}$ is $\left(\frac{3}{7}, \frac{1}{2} \right)$ $\left[\frac{3}{7}, \frac{1}{2} \right)$ $\left[\frac{3}{7}, \frac{8}{9} \right)$ $\left[\frac{4}{9}, \frac{8}{9} \right]$
1 vote
4
$f(x) = \dfrac{x^{2} + 2x – 15}{x^{2} – 7x – 18}$ is negative if and only if $– 2 < x < 3 \; \text{or} \; x > 9$ $x < – 5 \; \text{or} \; 3 < x < 9$ $– 5 < x < – 2 \; \text{or} \; 3 < x < 9$ $x < – 5 \; \text{or} \; – 2 < x < 3$
1 vote
5
If $f(x+y) = f(x) f(y)$ and $f(5) = 4,$ then $f(10) – f(-10)$ is equal to $0$ $15.9375$ $3$ $14.0625$
6
Let $f(x) = x^{2} + ax + b$ and $g(x) = f(x+1) – f(x-1).$ If $f(x) \geq 0$ for all real $x,$ and $g(20) = 72,$ then the smallest possible value of $b$ is $1$ $16$ $0$ $4$
1 vote
7
If $f\left ( 5+x \right )= f\left ( 5-x \right )$ for every real $x,$ and $f\left ( x \right )=0$ has four distinct real roots, then the sum of these roots is $0$ $40$ $10$ $20$
1 vote
8
Let $f$ be a function such that $f (mn) = f (m) f (n)$ for every positive integers $m$ and $n$. If $f (1), f (2)$ and $f (3)$ are positive integers, $f (1) < f (2),$ and $f (24) = 54$, then $f (18)$ equals _______
9
If $f(x+2)=f(x)+f(x+1)$ for all positive integers $x$, and $f(11)=91,f(15)=617$, then $f(10)$ equals ________
1 vote
10
Let $f\left ( x \right )=x^{2}$ and $g\left ( x \right )=2^{x}$, for all real $x$. Then the value of $f \left ( f\left ( g\left ( x \right ) \right )+g\left( f\left ( x \right ) \right ) \right)$ at $x=1$ is $16$ $18$ $36$ $40$
1 vote
11
Let $f\left ( x \right )=2x-5$ and $g\left ( x \right )=7-2x.$ Then $\mid f\left ( x \right ) + g\left ( x \right ) \mid=\mid f(x) \mid + \mid g\left ( x \right ) \mid$ if and only if $5/2<x<7/2$ $x\leq 5/2$ or $x\geq 7/2$ $x< 5/2$ or $x\geq 7/2$ $5/2\leq x\leq 7/2$
1 vote
12
If $f\left ( ab \right )=f\left ( a \right )f\left ( b \right )$ for all positive integers $a$ and $b$, then the largest possible value of $f\left (1\right )$ is $1$ $2$ $0$ $3$
1 vote
13
If $f( x)=\dfrac{5x+2}{ 3x-5}$ and $g( x )=x^{2}-2x-1,$ then the value of $g( f( f( 3 ) ) )$ is $2$ $1/3$ $6$ $2/3$
1 vote
14
$A, S, M$ and $D$ are functions of $x$ and $y$, and they are defined as follows. $A(x, y) = x + y$ $M(x, y) = xy$ $S(x,y)= x-y$ $D(x,y)= x/y, y\neq 0$ What is the value of $M(M(A(M(x, y), S(y, x)), x), A(y, x))$ for $x = 2, y = 3$? $60$ $140$ $25$ $70$
15
The set of all positive integers is the union of two disjoint subsets$:\left \{ f\left ( 1 \right ),f\left ( 2 \right ), \dots, f\left ( n \right ), \dots \right \}$ and $\left \{ g\left ( 1 \right ),g\left ( 2 \right ), \dots, g\left ( n \right ), \dots \right \}$, ... $n \geq 1$. What is the value of $g\left ( 1 \right )?$ $0$ $2$ $1$ Cannot be determined
1 vote
16
For all non-negative integers $x$ and $y$, $f(x,y)$ is defined as below. $f( 0,y) = y+1$ $f(x+1,0) = f( x, 1)$ $f( x+1, y+1) = f\left( x,f( x+1,y) \right)$ Then what is the value of $f(1,2)$ ________
1 vote
17
$\begin{array}{}Let\;f_{n+1}(x)&=f_n(x)+1\;\text{if$n$is a multiple of 3}\\ &=f_n(x)-1\;\text{otherwise.}\end{array}$ If $f_1(1)=0$, then what is $f_{50}(1)$? $-18$ $-16$ $-17$ Cannot be determined
18
Consider the function given by $f(x) =\mid x-1\mid-x$ What is the area of the triangle bounded by the graph of the given function with the coordinate axis given by $x=0\:\text{and}\:y=0$? $2$ $\large\frac{1}{4}$ $\large\frac{1}{2}$ $1$
19
The graphs given alongside represent two functions $f(x)\:\text{and}\:g(x)$ respectively. Which of the following is true? $g(x)=[f(x)]$ $g(x)=f(-x)$ $g(x)=-f(x)$ None of these
20
Consider the function given by $f(x) =\mid x-1\mid-x$ Which of the following is not true about the graph of $f(x)$? A portion of the graph is parallel to the line $y = 25$. A portion of graph is in 2nd quadrant. Some portion of graph lies in 1st quadrant. Some portion of graph lies in 3rd quadrant.
1 vote
21
For any positive integer $n$, let $f(n)=n(n+1)$ if n is even, and $f(n)=n+3$ if n is odd. if $m$ is a positive integer such that $8f(m+1)-f(m)=2$, then $m$ equals _______
1 vote
22
Consider a function $f$ satisfying $f(x+y)=f(x)f(y)$ where $x,y$ are positive integers, and $f(1)=2$. If $f(a+1)+f(a+2)+\ldots +f(a+n)=16(2^{n}-1)$ then $a$ is equal to ______
23
If $g(x)=p\mid x \mid-qx^2$, where $p$ and $q$ are constants, then at $x=0, g(x)$ will be maximum when $p>0,q>0$ minimum when $p<0,q<0$ minimum when $p>0,q<0$ maximum when $p>0,q<0$
24
Let $f(x)= \dfrac{1}{1+x^2}$ and $g(x)=\dfrac{e^{−x}}{1+[x]}$, where $[x]$ is the greatest integer less than or equal to $x$. Then which of the following domain is true? domain of $(f+g)=R-(-2,-1]$ domain of $(f+g)=R-[-1,0)$ ... Both II and IV Both I and III Both I and IV Both II and III
25
Let $f$ be an injective map with domain $\left \{ x, y, z \right \}$ and the range $\left \{ 1, 2, 3 \right \}$ such that exactly one of the following statements is correct and the remaining are false. $f\left \{x \right \}=1,f\left ( y \right )\neq 1,f\left ( z \right )\neq 2.$ The value of $f^{-1}\left ( 1 \right )$ is $x$ $y$ $z$ None of the above
26
Answer the question based on the information given below: Let x and y be real numbers and let $f(x, y) = |x+y|, F(f(x, y)) = -f(x,y) \text{ and } G(f(x, y)) = -F(f(x, y))$ Which of the following expressions yields $x^2$ as a result? $F(f(x, -x)).G(f(x, -x))$ $F(f(x, x)).G(f(x, x)).4$ $-F(f(x, x)).G(f(x, -x)) \: \log_2 16$ $f(x,x).f(x,x)$
27
Answer the question based on the information given below: Let x and y be real numbers and let $f(x, y) = |x+y|, F(f(x, y)) = -f(x,y) \text{ and } G(f(x, y)) = -F(f(x, y))$ Which of the following statements is true? $F(f(x,y)) .G(f(x,y)) = -F(f(x,y)).G(f(x,y))$ $F(f(x,y)) .G(f(x,y)) > -F(f(x,y)).G(f(x,y))$ $F(f(x,y)) .G(f(x,y)) \neq G(f(x,y)).F(f(x,y))$ $F(f(x,y)) +G(f(x,y)) + f(x,y)= f(-x,-y)$
28
Answer the following question based on the information given below. For real numbers $x, y,$ let $f(x, y) = \left\{\begin{matrix} \text{Positive square-root of}\; (x + y),\;\text{if}\; (x + y)^{0.5}\;\text{is real} \\ (x + y)^2,\;\text{otherwise} \end{matrix}\right.$ ... than $g(x, y)?$ Both $x$ and $y$ are less than $-1$ Both $x$ and $y$ are positive Both $x$ and $y$ are negative $y > x$
29
Answer the following question based on the information given below. For three distinct real numbers $x, y$ and $z,$ let $f(x, y, z) = \min(\max(x, y), \max(y, z), \max(z, x))$ $g(x, y, z) = \max(\min(x, y), \min(y, z), \min(z, x))$ $h(x, y, z) = \max(\max(x, y), \max(y, z), \max(z, x))$ ... $(h(x, y, z) - f(x, y, z))/(n(x, y, z) - g(x, y, z))$
30
Answer the following question based on the information given below. For three distinct real numbers $x, y$ and $z,$ let $f(x, y, z) = \min(\max(x, y), \max(y, z), \max(z, x))$ $g(x, y, z) = \max(\min(x, y), \min(y, z), \min(z, x))$ $h(x, y, z) = \max(\max(x, y), \max(y, z), \max(z, x))$ ... $(j(x, y, z) - g(x, y, z))/h(x, y, z)$ $(f(x, y, z) - h(x, y, z))/f(x, y, z)$
31
Use the following information for next two questions: A function $f(x)$ is said to be even if $f(-x) = f(x)$, and odd if $f(-x) = -f(x)$. Thus, for example, the function given by $f(x)=x^{2}$ is even, while the function given by ... following questions. The sum of two odd functions is always an even function is always an odd function is sometimes odd and sometimes even may be neither odd nor even
32
Answer the following question based on the information given below. For a real number $x,$ let f(x) = 1/(1 + x), if x is non-negative = 1+ x, if x is negative f$^n$(x) = f(f$^{n – 1}$(x)), n = 2, 3, .... $r$ is an integer $\geq 2.$ Then what is the value of $f^{r-1}(-r) + f^r(-r)+f^{r+1}(-r)$? $-1$ $0$ $1$ None of these
33
Answer the following question based on the information given below. Given below is a graph made up of straight-line segments shown as thick lines. Choose the answer as if $f(x) = 3 f(–x);$ if $f(x) = –f(–x);$ if $f(x) = f(–x);$ and if $3 f(x) = 6 f(–x),$ for $x\geq 0.$ $1$ $2$ $3$ $4$
34
Answer the following question based on the information given below. Given below is a graph made up of straight-line segments shown as thick lines. Choose the answer as if $f(x) = 3 f(–x);$ if $f(x) = –f(–x);$ if $f(x) = f(–x);$ and if $3 f(x) = 6 f(–x),$ for $x\geq 0.$ $1$ $2$ $3$ $4$
35
For all non-negative integers $x$ and $y, f(x, y)$ is defined as below $f(0, y) = y + 1$ $f(x + 1, 0) = f(x, 1)$ $f(x + 1,y + 1) = f(x, f(x + 1, y))$ Then, what is the value of $f(1, 2)?$ Two Four Three Cannot be determined
36
The set of all positive integers is the union of two disjoint subsets $\{f(1), f(2),\dots ,f(n),\dots\}$ and $\{g(1), g(2),\dots,g(n),\dots\},$ where $f(1) < f(2) <\dots < f(n) < \dots,$ and $g(1) < g(2) <\dots< g(n) < \dots,$ and $g(n) = f(f(n)) + 1$ for all $n \geq 1.$ What is the value of $g(1)?$ Zero Two One Cannot be determined
37
Answer the following question based on the information given below. For a real number $x$, let f(x) = 1/(1 + x), if x is non-negative = 1+ x, if x is negative f$^n$(x) = f(f$^{n – 1}$(x)), n = 2, 3, .... What is the value of the product, $f(2)f^2(2)f^3(2)f^4(2)f^5(2)$? $\frac{1}{3}$ $3$ $\frac{1}{18}$ None of these
Answer the following question based on the information given below. Given below is a graph made up of straight-line segments shown as thick lines. Choose the answer as if $f(x) = 3 f(–x);$ if $f(x) = –f(–x);$ if $f(x) = f(–x);$ and if $3 f(x) = 6 f(–x),$ for $x\geq 0.$ $1$ $2$ $3$ $4$
Answer the following question based on the information given below. For three distinct real numbers $x, y$ and $z,$ let $f(x, y, z) = \min(\max(x, y), \max(y, z), \max(z, x))$ $g(x, y, z) = \max(\min(x, y), \min(y, z), \min(z, x))$ $h(x, y, z) = \max(\max(x, y), \max(y, z), \max(z, x))$ ... $j(x, y, z)/h(x, y, z)$ $f(x, y, z)/g(x, y, z)$ $(f(x, y, z) + h(x, y, z) - g(x, y, z))/j(x, y, z)$
Answer the following question based on the information given below. For real numbers $x, y,$ let $f(x, y) = \left\{\begin{matrix} \text{Positive square-root of}\; (x + y),\;\text{if}\; (x + y)^{0.5}\;\text{is real} \\ (x + y)^2,\;\text{otherwise} \end{matrix}\right.$ ... $f(x, y) - (g(x, y))^2$ $g(x, y) - (f(x, y))^2$ $f(x, y) + g(x, y)$