Tag: functions and graphs

Questions Related to functions and graphs

If $y^2 = ax^2 +bx+c$, then $y^2 \dfrac{d^2y}{dx^2}$ is

  1. a constant function

  2. a function of x only

  3. a function of y only

  4. a function of both x and y


Correct Option: A

If $fxln\left(1+\dfrac{1}{x}\right)dx=p(x)ln\left(1+\dfrac{1}{x}\right)+\dfrac{1}{2}x-\dfrac{1}{2}ln(1+x)+c$, being arbitary costant, then

  1. $p(X)=\dfrac{1}{2}x^{2}$

  2. $p(x)=0$

  3. $p(x)=1$

  4. $none\ of\ these$


Correct Option: A

Let $f(x)$ is cubic polynomial with real coefficient such that $f''(3) = 0, f'(5) = 0$. If $f(3) = 1$ and $f(5) = -3$, then $f(1)$ is equal to

  1. $2$

  2. $3$

  3. $5$

  4. $6$


Correct Option: A

$f (x) = x^4 - 10x^3 + 35x^2 - 50x + c$ is a constant. the number of real roots of . f (x) = 0 and 
f'' (x) = 0 are respectively 

  1. 1 , 0

  2. 3, 2

  3. 1 , 2

  4. 3 , 0


Correct Option: A

The positive integers $x$ for which $f(x)=x^{3}-8x^{2}+20x-13$ is a prime is

  1. $2$

  2. $3$

  3. $4$

  4. $5$


Correct Option: A

If $f\quad \left( x \right) ={ x }^{ 2 }+2bx+{ 2c }^{ 2 }\quad and\quad g\quad (x)\quad ={ -x }^{ 2 }\quad -2cx+{ b }^{ 2 }\quad are\quad such\quad that\quad min\quad f\quad (x)\quad >\quad max\quad g\quad (x),\quad then$ relation between b and c, is

  1. none relation

  2. 0 < c < b/2

  3. $\left| c \right| <\frac { \left| b \right| }{ \sqrt { 2 } } $

  4. $\left| c \right| >\sqrt { 2 } \left| b \right| $


Correct Option: A

If $f(x)$ is a polynomial function satisfying $f(x)f\left(\dfrac{1}{x}\right)=f(x)+\left(\dfrac{1}{x}\right)$ and $f(3)=28$, then $f(4)=$

  1. $63$

  2. $65$

  3. $66$

  4. $27$


Correct Option: A

If $f\left(x\right)$ is a polynomial such that $ f\left(a\right) f\left(b\right)<0$, then number of zeros lieing between $a$ and $b$ is 

  1. $one$

  2. $at least one$

  3. $two$

  4. $at most 2$


Correct Option: A

If $ P ( X ) = x ^ { 3 } - 3 x ^ { 2 } + 2 x + 5 $ and P ( a ) = P ( b ) = P ( c ) = 0 then the value of ( 2 - a ) ( 2 - b ) ( 2 - c ) is

  1. 3

  2. 5

  3. 7

  4. 9


Correct Option: A

If f : R $\rightarrow$ R, g : R $\rightarrow$ R and h : R $\rightarrow$ R is such that $f(x) = x^2, g(x) = tan  x$ and $h(x) = log  x$, then the value of [ho(gof)], if $x = \displaystyle \dfrac{\pi}{2}$ will be

  1. 0

  2. 1

  3. -1

  4. 10


Correct Option: A
Explanation:

$ho(gof) =(hof)(f(x))$
$=(hog)(x^2)=(hof) (\dfrac{\pi}{4}) = h(g(\dfrac{\pi}{4}))$
$= h(tan \dfrac{ \pi}{4}) = h(1) = log 1 =0$