Explore topic-wise MCQs in Joint Entrance Exam - Main (JEE Main).

This section includes 8666 Mcqs, each offering curated multiple-choice questions to sharpen your Joint Entrance Exam - Main (JEE Main) knowledge and support exam preparation. Choose a topic below to get started.

6651.

If \[f(x)=\left\{ \begin{align}   & x,\ \ \text{when}0

A.            \[\underset{x\to 1/2+}{\mathop{\lim }}\,f(x)=2\]                      
B.            \[\underset{x\to 1/2-}{\mathop{\lim }}\,f(x)=2\]
C.            \[f(x)\]is continuous at \[x=\frac{1}{2}\]                                    
D.            \[f(x)\]is discontinuous at \[x=\frac{1}{2}\]
Answer» E.
6652.

If \[f(x)=\left\{ \begin{align}   & \frac{1-\cos x}{x},\,x\ne 0 \\  & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,k,\,x=0 \\ \end{align} \right.\]is continuous at \[x=0\] then \[k=\] [Karnataka CET 2004]

A.            0
B.            \[\frac{1}{2}\]
C.            \[\frac{1}{4}\]
D.            \[-\frac{1}{2}\]
Answer» B.            \[\frac{1}{2}\]
6653.

The function \[f(x)=\frac{1-\sin x+\cos x}{1+\sin x+\cos x}\] is not defined at \[x=\pi .\] The value of \[f(\pi ),\] so that \[f(x)\] is continuous at \[x=\pi \], is [Orissa JEE 2003]

A.            \[-\frac{1}{2}\]
B.            \[\frac{1}{2}\]
C.            ? 1
D.            1
Answer» D.            1
6654.

If \[f(x)\,=\,\left\{ \begin{matrix}    \frac{\sqrt{1+kx}-\sqrt{1-kx}}{x} & \text{,for}-1\le x

A.            ? 4
B.            ? 3
C.            ? 2
D.            ? 1
Answer» D.            ? 1
6655.

For the function \[f(x)\,=\frac{{{\log }_{e}}(1+x)-{{\log }_{e}}(1-x)}{x}\] to be continuous at \[x=0,\] the value of \[f(0),\] should be  [MP PET 2003]

A.            ?1
B.            0
C.            ?2
D.            2
Answer» E.
6656.

The function defined by \[f(x)\,=\,\left\{ \begin{matrix}    {{\left( {{x}^{2}}+{{e}^{\frac{1}{2-x}}} \right)}^{-1}} & , & x\ne 2  \\    k & , & x=2  \\ \end{matrix} \right.\], is continuous from right at the point x = 2, then k is equal to [Orissa JEE 2002]

A.            0
B.            1/4
C.            ?1/4
D.            None of these
Answer» C.            ?1/4
6657.

If \[f(x)=\left\{ \begin{matrix}    \frac{{{x}^{2}}-9}{x-3}\,, & \text{if }x\ne 3  \\    2x+k\,, & \text{otherwise}  \\ \end{matrix} \right.\], is continuous at \[x=3,\] then \[k=\]                  [Kerala (Engg.) 2002]

A.            3
B.            0
C.            ?6
D.            1/6
Answer» C.            ?6
6658.

If function \[f(x)=\left\{ \begin{matrix}    x\,\,\,\,\,, & \text{if}\,x\,\text{is rational}  \\    1-x, & \text{if}\,x\,\text{is irrational}  \\ \end{matrix}, \right.\] then \[f(x)\] is continuous at ...... number of points [UPSEAT 2002]

A.            \[\infty \]
B.            1
C.            0
D.            None of these
Answer» D.            None of these
6659.

If \[f(x)\,=\frac{2-\sqrt{x+4}}{\sin 2x},\,\,(x\ne 0),\] is continuous function at \[x=0\], then \[f(0)\] equals    [MP PET 2002]

A.            \[\frac{1}{4}\]
B.            \[-\frac{1}{4}\]
C.            \[\frac{1}{8}\]
D.            \[-\frac{1}{8}\]
Answer» E.
6660.

Let \[f(x)=\,\left\{ \begin{matrix}    \frac{\sin \pi x}{5x}, & x\ne 0  \\    k, & x=0  \\ \end{matrix} \right.\]. If \[f(x)\] is continuous at \[x=0,\] then \[k=\]  [Karnataka CET 2002]

A.            \[\frac{\pi }{5}\]
B.            \[\frac{5}{\pi }\]
C.            1
D.            0
Answer» B.            \[\frac{5}{\pi }\]
6661.

If \[f(x)=\left\{ \begin{matrix}    \frac{1-\sin x}{\pi -2x}, & x\ne \frac{\pi }{2}  \\    \,\,\,\,\,\,\,\,\,\,\,\,\,\lambda \,, & x=\frac{\pi }{2}  \\ \end{matrix} \right.\], be continuous at \[x=\pi /2,\] then value of \[\lambda \] is                                           [RPET 2002]

A.            ?1
B.            1           
C.            0
D.            2
Answer» D.            2
6662.

In order that the function\[f(x)={{(x+1)}^{1/x}}\]is continuous at \[x=0\], \[f(0)\]must be defined as              [MNR 1989]

A.            \[f(0)=0\]
B.            \[f(0)=e\]
C.            \[f(0)=1/e\]
D.            \[f(0)=1\]
Answer» C.            \[f(0)=1/e\]
6663.

If \[f(x)=\,|x|\], then \[f(x)\] is [DCE 2002]

A.            Continuous for all x
B.            Differentiable at \[x=0\]
C.                    Neither continuous nor differentiable at \[x=0\]
D.            None of these
Answer» B.            Differentiable at \[x=0\]
6664.

The function \[f(x)=\sin |x|\] is                  [DCE 2002]

A.            Continuous for all x
B.            Continuous only at certain points
C.            Differentiable at all points
D.            None of these
Answer» B.            Continuous only at certain points
6665.

In order that the function \[f(x)={{(x+1)}^{\cot \,x}}\] is continuous at \[x=0\], \[f(0)\] must be defined as [UPSEAT 2000; Kurukshetra CEE 2001; Pb. CET 2004]

A.            \[f(0)=\frac{1}{e}\]
B.            \[f(0)=0\]           
C.            \[f(0)=e\]
D.            None of these
Answer» D.            None of these
6666.

If \[f(x)=\frac{{{x}^{2}}-10x+25}{{{x}^{2}}-7x+10}\] for \[x\]\[\ne \,\]5 and f is continuous at \[x=5,\] then \[f(5)=\] [EAMCET 2001]

A.            0
B.            5
C.            10
D.            25
Answer» B.            5
6667.

The values of A and B such that the function \[f(x)=\left\{ \begin{matrix}    -2\sin x, & x\le -\frac{\pi }{2}  \\    A\sin x+B, & -\frac{\pi }{2}

A.            \[A=0,\,B=1\]
B.            \[A=1,\,B=1\]
C.            \[A=-1,\,B=1\]
D.            \[A=-1,\,B=0\]
Answer» D.            \[A=-1,\,B=0\]
6668.

If the function \[f(x)=\,\left\{ \begin{matrix}    5x-4 & , & \text{if} & 0

A.            ? 1
B.            0
C.            1
D.            None of these
Answer» B.            0
6669.

The function \[f(x)\,=\left\{ \begin{align}   & x+2\,\,\,\,,\,\,\,1\le x\le 2 \\  & 4\,\,\,\,\,\,\,\,\,\,\,,\,\,\,x=2 \\  & 3x-2\,\,,\,\,\,x>2 \\ \end{align} \right.\] is continuous at [DCE 1999]

A.            \[x=2\] only
B.            \[x\le 2\]
C.            \[x\ge 2\]
D.            None of these
Answer» D.            None of these
6670.

If \[f(x)=\left\{ \begin{align}   & \,\,\,\,\,\,\,\frac{\sin [x]}{[x]+1},\,\,\text{for}\,x>0 \\  & \frac{\cos \frac{\pi }{2}[x]}{[x]},\,\,\text{for}\,x

A.            Equal to 0
B.            Equal to 1
C.            Equal to ?1
D.            Indeterminate
Answer» B.            Equal to 1
6671.

If the function \[f(x)=\left\{ \begin{align}   & 1+\sin \frac{\pi x}{2}\,\,,\,\text{for}\,-\infty

A.            0, 2
B.            1, 1
C.            2, 0
D.            2, 1
Answer» D.            2, 1
6672.

Function \[f(x)=\left\{ \begin{align}   & \,\,\,x-1,\ x

A.            For all real values of x              
B.            For \[x=2\]only
C.            For all real values of x such that \[x\ne 2\]
D.            For all integral values of x only
Answer» B.            For \[x=2\]only
6673.

If the function \[f(x)=\left\{ \begin{align}   & {{(\cos x)}^{1/x}},\ x\ne 0 \\  & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,k,\,x=0 \\ \end{align} \right.\]is continuous at \[x=0\], then the value of k is                     [Kurukshetra CEE 1996]

A.            1
B.            ?1
C.            0
D.            e
Answer» B.            ?1
6674.

Let \[f(x)=\left\{ \begin{align}   & \frac{{{x}^{4}}-5{{x}^{2}}+4}{|(x-1)(x-2)|},\ \ x\ne 1,\ 2 \\  & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,6,\,\,\,x=1 \\  & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,12,\,\,\,x=2 \\ \end{align} \right.\] Then \[f(x)\]is continuous on the set

A.            R
B.            \[R-\{1\}\]
C.            \[R-\{2\}\]
D.            \[f:R\to R\]
Answer» E.
6675.

Let \[f(x)=\left\{ \begin{align}   & \frac{x-4}{|x-4|}+a,\ x4 \\ \end{align} \right.\]. Then \[f(x)\]is continuous at \[x=4\] when

A.            \[a=0,\ b=0\]
B.            \[a=1,\ b=1\]
C.            \[a=-1,\ b=1\]
D.            \[a=1,\ b=-1\]
Answer» E.
6676.

If \[f(x)=\left\{ \begin{align}   & \sin x,\ x\ne n\pi ,\ \ n\in Z \\  & \,\,\,\,\,\,2,\,\text{otherwise} \\ \end{align} \right.\] and \[g(x)=\left\{ \begin{align}   & {{x}^{2}}+1,\ x\ne 0,\,2 \\  & \,\,\,\,\,\,\,\,\,4,\,x=0 \\  & \,\,\,\,\,\,\,\,\,\,5,x=2 \\ \end{align} \right.,\]  then \[\underset{x\to 0}{\mathop{\lim }}\,g\,\{f(x)\}\] is [Kurukshetra CEE 1996]

A.            5
B.            6
C.            7
D.            1
Answer» E.
6677.

The value of k which makes \[f(x)=\left\{ \begin{align}   & \sin \frac{1}{x},\ x\ne 0 \\  & \,\,\,\,\,\,\,\,k,\,x=0 \\ \end{align} \right.\] continuous at \[x=0\]is                                                                         [MNR 1995]

A.            8
B.            1
C.            ?1
D.            None of these
Answer» E.
6678.

If \[f(x)=\left\{ \begin{align}   & x+\lambda ,\ x\,3 \\ \end{align} \right.\]is continuous at\[x=3\], then \[\lambda =\] [MP PET 1994, 2001; RPET 1999]

A.            4
B.            3
C.            2
D.            1
Answer» E.
6679.

If \[f(x)=\left\{ \begin{align}   & \frac{{{x}^{2}}+3x-10}{{{x}^{2}}+2x-15},\ \ \text{when }x\ne -5 \\  & \,\,a\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,,\text{when }x=-5 \\ \end{align} \right.\]is continuous at \[x=-5\], then the value of 'a' will be         [MP PET 1987]

A.            \[\frac{3}{2}\]
B.            \[\frac{7}{8}\]
C.            \[\frac{8}{7}\]
D.            \[\frac{2}{3}\]
Answer» C.            \[\frac{8}{7}\]
6680.

If \[f(x)=\left\{ \begin{align}   & \,\,\,\,{{x}^{2}},\,\text{when}\,x\le 1 \\  & x+5,\text{when }x>\text{1} \\ \end{align} \right.\], then [AISSE 1983]

A.            \[f(x)\]is continuous at \[x=1\]
B.            \[f(x)\]is discontinuous at\[x=1\]
C.            \[\underset{x\to 1}{\mathop{\lim }}\,f(x)=1\]                           
D.            None of these
Answer» C.            \[\underset{x\to 1}{\mathop{\lim }}\,f(x)=1\]                           
6681.

Let \[f(x)=\left\{ \begin{align}   & \frac{{{x}^{3}}+{{x}^{2}}-16x+20}{{{(x-2)}^{2}}},\text{if}\ x\ne 2 \\  & \ \ \ \ \ \,\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \,\ k,\ \text{if}\ x=2 \\ \end{align} \right.\].  If \[f(x)\] be continuous for all x, then k =                                        [IIT 1981]

A.            7
B.            ?7
C.            \[\pm 7\]
D.            None of these
Answer» B.            ?7
6682.

If \[f(x)=\left\{ \begin{align}   & \frac{x-|x|}{x},\text{when}\,x\ne 0 \\  & \,\,\,\,\,\,\,\,\,\,\,\,\,2,\,\text{when}\,x=0 \\ \end{align} \right.\], then                    [AI CBSE 1982]

A.            \[f(x)\]is continuous at \[x=0\]
B.            \[\left[ 0,\frac{\pi }{2} \right]\]is discontinuous at \[x=0\]
C.            \[\underset{x\to 0}{\mathop{\lim }}\,f(x)=2\]                           
D.            None of these
Answer» C.            \[\underset{x\to 0}{\mathop{\lim }}\,f(x)=2\]                           
6683.

If \[f(x)=\left\{ \begin{align}   & a{{x}^{2}}-b,\,\,\text{when }0\le x

A.            \[a=2,\ b=0\]
B.            \[a=1,\ b=-1\]
C.            \[a=4,\ b=2\]
D.            All the above
Answer» E.
6684.

If \[f(x)=\left\{ \begin{align}   & \,\,\,\,\,\,\,\,\,\frac{1-\cos 4x}{{{x}^{2}}},\ \ \text{when}\,x0 \\ \end{align} \right.\],            is continuous at \[x=0\], then the value of 'a' will be                                                                                 [IIT 1990; AMU 2000]

A.            8
B.            ?8
C.            4
D.            None of these
Answer» B.            ?8
6685.

If \[f(x)=\left\{ \begin{align}   & \,\,\,\,\,\,\,\,\,\,\,\,x\sin x,\,\text{when }0

A.            \[f(x)\]is discontinuous at \[x=\pi /2\]
B.            \[f(x)\]is continuous at \[x=\pi /2\]
C.            \[f(x)\]is continuous at \[x=0\]
D.            None of these
Answer» B.            \[f(x)\]is continuous at \[x=\pi /2\]
6686.

If \[f(x)=\left\{ \begin{align}   & 1+x,\ \text{when }x\le 2 \\  & 5-x,\,\text{when }\,x\le 3 \\ \end{align} \right.\], then

A.            \[f(x)\]is continuous at \[x=2\]
B.            \[f(x)\]is discontinuous at \[A=0,\,B=1\]
C.            \[f(x)\]is continuous at\[x=3\] 
D.            None of these
Answer» B.            \[f(x)\]is discontinuous at \[A=0,\,B=1\]
6687.

If \[f(x)=\left\{ \begin{align}   & {{x}^{2}},\,\,\text{when}\,\,\,x\ne 1 \\  & \,\,\,2,\text{when}\,\,x=1 \\ \end{align} \right.\]then

A.            \[\underset{x\to 1}{\mathop{\lim }}\,f(x)=2\]
B.            \[f(x)\]is continuous at \[x=1\]
C.            \[f(x)\]is discontinuous at \[x=1\]   
D.            None of these
Answer» D.            None of these
6688.

If\[f(x)=\left\{ \begin{align}   & \frac{|x-a|}{x-a},\text{when}\,x\ne a \\  & \,\,\,\,\,\,\,\,\,\,\,\,\,\,1,\text{when}\,x=a \\ \end{align} \right.\],then                             [AI CBSE 1983]

A.            \[f(x)\]is continuous at \[x=a\]
B.            \[f(x)\]is discontinuous at \[x=a\]
C.            \[\underset{x\to a}{\mathop{\lim }}\,f(x)=1\]
D.            None of these
Answer» C.            \[\underset{x\to a}{\mathop{\lim }}\,f(x)=1\]
6689.

If \[f(x)=|x-b|,\]then function                                          [AI CBSE 1984]

A.            Is continuous at \[x=1\]
B.            Is continuous at \[x=b\]
C.            Is discontinuous at\[x=b\]
D.            None of these
Answer» C.            Is discontinuous at\[x=b\]
6690.

The function \[f(x)=\frac{\log (1+ax)-\log (1-bx)}{x}\]is not defined at \[x=0\]. The value which should be assigned to f at x =0 so that it is continuos at \[x=0\], is [IIT 1983; MP PET 1995; Karnataka CET 1999; Kurukshetra CEE 2002; AMU 2002]

A.            \[a-b\]
B.            \[a+b\]
C.            \[\log a+\log b\]
D.            \[\log a-\log b\]
Answer» C.            \[\log a+\log b\]
6691.

If \[f(x)=\left\{ \begin{align}   & \frac{5}{2}-x\,,\,\text{when}\,x2 \\ \end{align} \right.\], then

A.            \[f(x)\]is continuous at \[x=2\]
B.            \[f(x)\]is discontinuous at \[x=2\]
C.            \[\underset{x\to 2}{\mathop{\lim }}\,f(x)=1\]
D.            None of these
Answer» C.            \[\underset{x\to 2}{\mathop{\lim }}\,f(x)=1\]
6692.

If \[f(x)=\left\{ \begin{align}   & \frac{{{x}^{2}}-1}{x+1},\,\text{when }x\ne -1 \\  & \,\,\,\,\,\,\,\,-2,\,\text{when }x=-1 \\ \end{align} \right.\],then

A.            \[\underset{x\to {{(-1)}^{-}}}{\mathop{\lim }}\,f(x)=-2\]
B.            \[\underset{x\to {{(-1)}^{+}}}{\mathop{\lim }}\,f(x)=-2\]
C.            \[f(x)\]is continuous at \[x=-1\]
D.            All the above are correct
Answer» E.
6693.

If \[f(x)=\left\{ \begin{align}   & 1+{{x}^{2}},\,\,\,\text{when}\,0\le x\le 1 \\  & 1-x\,\,\,,\text{when}\,\,x>1 \\ \end{align} \right.\],  then

A.            \[\underset{x\to {{1}^{+}}}{\mathop{\lim }}\,f(x)\ne 0\]           
B.  \[\underset{x\to {{1}^{-}}}{\mathop{\lim }}\,f(x)\ne 2\]
C.  \[f(x)\]is discontinuous at \[x=1\]
D.            None of these
Answer» D.            None of these
6694.

If \[f(x)=\left\{ \begin{align}   & \frac{\sin 2x}{5x},\text{when}\,x\ne 0 \\  & \,\,\,\,\,\,\,\,\,\,\,\,k,\text{when }x=0 \\ \end{align} \right.\] is continuous at\[x=0\], then the value of k will be [AI CBSE 1991]

A.            1
B.            \[\frac{2}{5}\]
C.            \[-\frac{2}{5}\]
D.            None of these
Answer» C.            \[-\frac{2}{5}\]
6695.

If \[f(x)=\left\{ \begin{align}   & {{\sin }^{-1}}|x|,\text{when}\,x\ne 0 \\  & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,0,\,\text{when }x=0 \\ \end{align} \right.\] then

A.            \[\underset{x\to 0+}{\mathop{\lim }}\,f(x)\ne 0\]                     
B.            \[\underset{x\to 0-}{\mathop{\lim }}\,f(x)\ne 0\]
C.            \[f(x)\]is continuous at\[x=0\] 
D.            None of these
Answer» D.            None of these
6696.

If \[f(x)=\left\{ \begin{align}   & \,\,\,\,\,\,\,\,\,-{{x}^{2}},\,\text{when }x\le 0 \\  & \,\,\,\,\,5x-4,\,\text{when}0

A.            \[f:R\to R\]is continuous at \[x=0\]
B.            \[f(x)\] is continuous \[x=2\]
C.            \[f(x)\]is discontinuous at\[x=1\]
D.            None of these
Answer» C.            \[f(x)\]is discontinuous at\[x=1\]
6697.

For the function \[f(x)=\left\{ \begin{align}   & \frac{{{\sin }^{2}}ax}{{{x}^{2}}},\,\text{when}\,x\ne 0 \\  & \,\,\,\,\,\,\,\,\,\,\,\,\,\,1,\text{when}\,x=0 \\ \end{align} \right.\] which one is a true statement                              

A.            \[f(x)\]is continuous at \[x=0\]
B.            \[f(x)\]is discontinuous at \[x=0\], when \[a\ne \pm 1\]
C.            \[\underset{x\to 1}{\mathop{\lim }}\,(1-x+[x-1]+[1-x])\] is continuous at \[x=a\]
D.            None of these
Answer» C.            \[\underset{x\to 1}{\mathop{\lim }}\,(1-x+[x-1]+[1-x])\] is continuous at \[x=a\]
6698.

At which points the function\[f(x)=\frac{x}{[x]}\], where\[[.]\] is greatest integer function, is discontinuous

A.            Only positive integers               
B.            All positive and negative integers and (0, 1)
C.            All rational numbers
D.            None of these
Answer» C.            All rational numbers
6699.

Which of the following statements is true for graph \[f(x)=\log x\]     

A.            Graph shows that function is continuous
B.            Graph shows that function is discontinuous
C.            Graph finds for negative and positive values of x
D.            Graph is symmetric along x-axis
Answer» B.            Graph shows that function is discontinuous
6700.

If the function \[f(x)=\left\{ \begin{align}   & \frac{k\cos x}{\pi -2x},\text{when }x\ne \frac{\pi }{2} \\  & 3,\ \ \ \ \ \ \ \ \ \text{when }x=\frac{\pi }{2} \\ \end{align} \right.\] be continuous at \[x=\frac{\pi }{2}\], then k =      

A.            3
B.            6
C.            12
D.            None of these
Answer» C.            12