MCQ Bank
If first derivative is equal to zero, then these points are called ------------ .
- A) Double points
- B) Multiple points
- C) Critical points
- D) None of the other
$$The{\text{ }}critical{\text{ }}points{\text{ }}of{\text{ }}the{\text{ }}polynomial{\text{ }}p\left( x \right) = {x^3} - 3x + 1{\text{ }}are$$
- A) 0
- B) ±1
- C) 1
- D) -1
Which of the following is true for the function $f(x) = {x^{2\,}} - 2{\text{ }};\,x \in \mathbb{R}$
- A) It has an absolute maximum value at x = 0
- B) It does not have an absolute minimum value
- C) It has an absolute minimum value at x=0
- D) None of the others
$$In{\text{ }}curve{\text{ }}{y^2} = x{\left( {x - a} \right)^2},{\text{ }}the{\text{ }}singular{\text{ }}point{\text{ }}\left( {a,0} \right){\text{ }}is{\text{ }}a{\text{ }} \ldots \ldots \,when{\text{ }}{f_{xx}}\left( {a,0} \right) = {\text{ }} - 2a,{\text{ }}{f_{yy}}\left( {a,0} \right) = 2{\text{ }}and{\text{ }}{f_{xy}}\left( {a,0} \right) = 0.$$
- A) Conjugate point
- B) Node
- C) Cusp
- D) Isolated point
$$According{\text{ }}to{\text{ }}the{\text{ }}second{\text{ }}derivative{\text{ }}test{\text{ }}f{\text{ }}has{\text{ }}a{\text{ }}relative{\text{ }}maximum{\text{ }}value{\text{ }}at{\text{ }}c{\text{ }}if{\text{ }}f''\left( c \right)$$
- A) <0
- B) >0
- C) ≤0
- D) =0
The singular points of ${x^2}{(x - 3)^2}y'' + (x - 3)y' + 3{x^2}y = \,0$ are
- A) 1,3
- B) 4,3
- C) 0,3
- D) None of the other
$$If{\text{ }}f'\left( x \right) > 0{\text{ }}on{\text{ }}an{\text{ }}open{\text{ }}interval{\text{ }}extending{\text{ }}left{\text{ }}from{\text{ }}{x_0}\,and{\text{ }}f'\left( x \right) < 0{\text{ }}on{\text{ }}an{\text{ }}open{\text{ }}interval{\text{ }}extending{\text{ }}right{\text{ }}from{\text{ }}{x_0},{\text{ }}then{\text{ }}at{\text{ }}{x_0}\,the{\text{ }}f{\text{ }}has{\text{ }}a$$
- A) Relative minimum
- B) Relative extremum
- C) No maxima
- D) Relative maximum
$If{\text{ }}\frac{{df}}{{dx}}\, < \,0,\,\;at\,R(x,y),then$
- A) f(x) must has a critical point at R(x,y)
- B) f(x) is a decreasing function at R(x,y)
- C) None of the other
- D) f(x) is an increasing function at R(x,y)
Points of inflection and multiple points are the types of
- A) Singular point
- B) Double point
- C) None of these
- D) End points
$$The{\text{ }}critical{\text{ }}points{\text{ }}of{\text{ }}the{\text{ }}polynomial{\text{ }}p\left( x \right) = {x^3} - 2{x^2}\,are$$
- A) 0,4/3
- B) 2
- C) 0,-2
- D) ±2
Which of the following is true for the function $f(x) = 5{x^2} - 15x - 20{\text{ }};x \in \mathbb{R}$
- A) It has a critical point at x= 20
- B) It has no critical point
- C) It has a critical number at x = 3/2
- D) None of the other
$$According{\text{ }}to{\text{ }}the{\text{ }}second{\text{ }}derivative{\text{ }}test{\text{ }}f{\text{ }}has{\text{ }}a{\text{ }}relative{\text{ }}minimum{\text{ }}value{\text{ }}at{\text{ }}c{\text{ }}if{\text{ }}f''\left( c \right)$$
- A) ≥0
- B) >0
- C) =0
- D) <0
A critical number for a function “f” . . . . . . . . exist(s) in the domain of function.
- A) Always
- B) May or may not
- C) None of the above
- D) Does not
$$If{\text{ }}f'\left( x \right){\text{ }}has{\text{ }}the{\text{ }}same{\text{ }}sign{\text{ }}on{\text{ }}both{\text{ }}left{\text{ }}and{\text{ }}right{\text{ }}sides{\text{ }}of{\text{ }}{x_0}\,on{\text{ }}an{\text{ }}open{\text{ }}interval,{\text{ }}then{\text{ }}f.........\,relative{\text{ }}extremum/extrema{\text{ }}at{\text{ }}{x_0}.$$
- A) Three
- B) One
- C) Does not have
- D) Two
A function f has a local minimum at a point “d” if ……………….. in some open interval containing “d”.
- A) $f(d)f(x)\, = 0$
- B) $f(d) < f(x)\,$
- C) $f(d)f(x)\, \geqslant 0\,\,$
- D) $f(d) \geqslant f(x)$
$$If{\text{ }}f'\left( x \right) < 0{\text{ }}on{\text{ }}an{\text{ }}open{\text{ }}interval{\text{ }}extending{\text{ }}left{\text{ }}from{\text{ }}{x_0}\,and{\text{ }}f'\left( x \right) > 0{\text{ }}on{\text{ }}an{\text{ }}open{\text{ }}interval{\text{ }}extending{\text{ }}right{\text{ }}from{\text{ }}{x_0},{\text{ }}then{\text{ }}at{\text{ }}{x_0}\,the{\text{ }}f{\text{ }}has{\text{ }}a$$
- A) Relative minimum
- B) Relative maximum
- C) Relative extremum
- D) No maxima
$Let{\text{ f(x) = - 10x + 50, }}and{\text{ }}\frac{{df(x)}}{{dx}} < 0,\,then$
- A) f(x) is a decreasing function
- B) f(x) is an increasing function
- C) f(x) must has a critical point
- D) None of the other
To discuss the nature of a double point, we have to calculate the
- A) Normal
- B) Both (a) and (b)
- C) Binormal
- D) Tangents
A double point Q on a curve is a ……… if there exist no real points of the curve in the neighborhood of R.
- A) Conjugate point
- B) Both (b) and (c)
- C) Complex point
- D) Isolated point
$$For{\text{ }}the{\text{ }}curve{\text{ }}{x^3} + {y^3} - 3axy = 0,{\text{ }}the{\text{ }}tangents{\text{ }}at{\text{ }}the{\text{ }}origin{\text{ }}are{\text{ }}x = 0{\text{ }}and{\text{ }}y = 0,{\text{ }}then{\text{ }}the{\text{ }}origin{\text{ }}is{\text{ }}a$$
- A) Node
- B) Cusp
- C) Isolated point
- D) None of these