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.

4201.

\[\frac{1-2i}{2+i}+\frac{4-i}{3+2i}=\] [RPET 1987]

A. \[\frac{24}{13}+\frac{10}{13}i\]
B. \[\frac{24}{13}-\frac{10}{13}i\]
C. \[\frac{10}{13}+\frac{24}{13}i\]
D. \[\frac{10}{13}-\frac{24}{13}i\]
Answer» E.
4202.

The true statement is [Roorkee 1989]

A. \[1-i<1+i\]
B. \[2i+1>-2i+1\]
C. \[2i>1\]
D. None of these
Answer» E.
4203.

If  \[\frac{5(-8+6i)}{{{(1+i)}^{2}}}=a+ib\], then\[(a,\,b)\] equals [RPET 1986]

A. (15, 20)
B. (20, 15)
C. \[(-15,\,20)\]
D. None of these
Answer» B. (20, 15)
4204.

If \[z\ne 0\] is  a complex number, then

A. \[\operatorname{Re}(z)=0\Rightarrow \operatorname{Im}({{z}^{2}})=0\]
B.   \[\operatorname{Re}({{z}^{2}})=0\Rightarrow \operatorname{Im}({{z}^{2}})=0\]
C. \[\operatorname{Re}(z)=0\Rightarrow \operatorname{Re}({{z}^{2}})=0\]
D. None of these
Answer» B.   \[\operatorname{Re}({{z}^{2}})=0\Rightarrow \operatorname{Im}({{z}^{2}})=0\]
4205.

If \[{{\left( \frac{1+i}{1-i} \right)}^{m}}=1,\]then the least integral value of \[m\] is [IIT 1982; MNR 1984; UPSEAT 2001; MP PET 2002]

A. 2
B. 4
C. 8
D. None of these
Answer» C. 8
4206.

The real values of  \[x\] and \[y\] for which the equation \[({{x}^{4}}+2xi)-(3{{x}^{2}}+yi)=\]\[(3-5i)+(1+2yi)\] is satisfied, are [Roorkee 1984]

A. \[x=2,y=3\]
B. \[x=-2,y=\frac{1}{3}\]
C. Both (a) and (b)
D.  None of these
Answer» D.  None of these
4207.

The real values of \[x\]and\[y\]for which the equation is \[(x+iy)\] \[(2-3i)\]= \[4+i\] is satisfied, are [Roorkee 1978]

A. \[x=\frac{5}{13},y=\frac{8}{13}\]
B. \[x=\frac{8}{13},y=\frac{5}{13}\]
C. \[x=\frac{5}{13},y=\frac{14}{13}\]
D. None of these
Answer» D. None of these
4208.

\[{{\left\{ \frac{2i}{1+i} \right\}}^{2}}=\] [BIT Ranchi 1992]

A. 1
B. \[2i\]
C. \[\alpha -i\beta \,(\alpha ,\beta \,\text{real),}\]
D. \[\left( \frac{3-4ix}{3+4ix} \right)=\]
Answer» C. \[\alpha -i\beta \,(\alpha ,\beta \,\text{real),}\]
4209.

If \[{{(x+iy)}^{1/3}}=a+ib,\]then \[\frac{x}{a}+\frac{y}{b}\]is equal to [IT 1982; Karnataka CET 2000]

A. \[4({{a}^{2}}+{{b}^{2}})\]
B. \[4({{a}^{2}}-{{b}^{2}})\]
C. \[4({{b}^{2}}-{{a}^{2}})\]
D. None of these
Answer» C. \[4({{b}^{2}}-{{a}^{2}})\]
4210.

The real part of  \[{{(1-\cos \theta +2i\sin \theta )}^{-1}}\]is [IIT 1978, 86]

A. \[\frac{1}{3+5\cos \theta }\]
B. \[\frac{1}{5-3\cos \theta }\]
C. \[\frac{1}{3-5\cos \theta }\]
D. \[\frac{1}{5+3\cos \theta }\]
Answer» E.
4211.

\[\frac{3+2i\sin \theta }{1-2i\sin \theta }\] will be purely imaginary, if \[\theta =\] [IIT 1976; Pb. CET 2003]

A. \[2n\pi \pm \frac{\pi }{3}\]
B.   \[n\pi +\frac{\pi }{3}\]
C. \[n\pi \pm \frac{\pi }{3}\]
D. None of these [Where \[n\] is an integer]
Answer» D. None of these [Where \[n\] is an integer]
4212.

If \[{{a}^{2}}+{{b}^{2}}=1,\] then \[\frac{1+b+ia}{1+b-ia}=\]

A. 1
B. 2
C. \[b+ia\]
D. \[a+ib\]
Answer» D. \[a+ib\]
4213.

\[\frac{\sqrt{5+12i}+\sqrt{5-12i}}{\sqrt{5+12i}-\sqrt{5-12i}}=\]

A. \[-\frac{3}{2}i\]
B. \[\frac{3}{2}i\]
C. \[-\frac{3}{2}\]
D. \[\frac{3}{2}\]
Answer» B. \[\frac{3}{2}i\]
4214.

\[\frac{3+2i\sin \theta }{1-2i\sin \theta }\]will be real, if \[\theta \] =    [IIT 1976; EAMCET 2002]

A. \[2n\pi \]
B. \[n\pi +\frac{\pi }{2}\]
C. \[n\pi \]
D. None of these [Where \[n\] is an integer]
Answer» D. None of these [Where \[n\] is an integer]
4215.

If  \[n\] is a positive integer,  then \[{{\left( \frac{1+i}{1-i} \right)}^{4n+1}}\]=

A. 1
B. -1
C. \[i\]
D. \[-i\]
Answer» D. \[-i\]
4216.

\[\operatorname{Re}\frac{{{(1+i)}^{2}}}{3-i}\] =

A. \[-1/5\]
B. 44317
C. 44470
D. -0.1
Answer» B. 44317
4217.

Additive inverse of \[1-i\]is

A. \[0+0i\]
B. \[-1-i\]
C. \[-1+i\]
D. None of these
Answer» D. None of these
4218.

\[\left( \frac{1}{1-2i}+\frac{3}{1+i} \right)\,\,\left( \frac{3+4i}{2-4i} \right)=\] [Roorkee 1979; RPET 1999; Pb. CET 2003]

A. \[\frac{1}{2}+\frac{9}{2}i\]
B. \[\frac{1}{2}-\frac{9}{2}i\]
C. \[\frac{1}{4}-\frac{9}{4}i\]
D. \[\frac{1}{4}+\frac{9}{4}i\]
Answer» E.
4219.

If \[{{z}_{1}}\] and \[{{z}_{2}}\] be two complex number, then  Re\[({{z}_{1}}{{z}_{2}})=\]

A. Re \[({{z}_{1}}).\operatorname{Re}({{z}_{2}})\]
B. Re \[({{z}_{1}})\]. Im \[({{z}_{2}})\]
C. Im \[({{z}_{1}}).\operatorname{Re}\,({{z}_{2}})\]
D. None of these
Answer» E.
4220.

The values of \[x\] and \[y\] satisfying the equation \[\frac{(1+i)x-2i}{3+i}\] \[+\frac{(2-3i)\,y+i}{3-i}=i\] are [IIT 1980; MNR 1987]

A. \[x=-1,\,y=3\]
B. \[x=3,\,y=-1\]
C. \[x=0,\,y=1\]
D. \[x=1,y=0\]
Answer» C. \[x=0,\,y=1\]
4221.

The smallest positive integer \[n\]for which \[{{(1+i)}^{2n}}={{(1-i)}^{2n}}\]is  [Karnataka CET 2004]

A. 1
B. 2
C. 3
D. 4
Answer» C. 3
4222.

If \[x=3+i\],  then \[{{x}^{3}}-3{{x}^{2}}-8x+15=\] [UPSEAT 2003]

A. 6
B. 10
C. -18
D. -15
Answer» E.
4223.

If \[{{i}^{2}}=-1\], then sum \[i+{{i}^{2}}+{{i}^{3}}+...\]to 1000 terms is equal to [Kerala (Engg.) 2002]

A. 1
B. -1
C. i
D. 0
Answer» E.
4224.

The value of \[{{(1+i)}^{6}}+{{(1-i)}^{6}}\] is  [RPET 2002]

A. 0
B. 27
C. 26
D. None of these
Answer» B. 27
4225.

If \[n\] is a positive integer, then which of the following relations is false

A. \[{{i}^{4n}}=1\]
B. \[{{i}^{4n-1}}=i\]
C. \[{{i}^{4n+1}}=i\]
D. \[{{i}^{-4n}}=1\]
Answer» C. \[{{i}^{4n+1}}=i\]
4226.

\[{{(1+i)}^{10}}\], where \[{{i}^{2}}=-1,\] is equal to [AMU 2001]

A. 32 i
B. 64 + i
C. 24 i - 32
D. None of these
Answer» B. 64 + i
4227.

The value of \[{{i}^{n}}+{{i}^{n+1}}+{{i}^{n+2}}+{{i}^{n+3}}\,,\,(n\in N)\] is [RPET 2001]

A. 0
B. 1
C. 2
D. None of these
Answer» B. 1
4228.

The value of \[{{(1+i)}^{8}}+{{(1-i)}^{8}}\] is  [RPET 2001; KCET  2001]

A. 16
B. -16
C. 32
D. -32
Answer» D. -32
4229.

If \[\]\[x+\frac{1}{x}=2\cos \theta ,\] then x is equal to [RPET 2001]

A. \[\cos \theta +i\,\sin \theta \]
B. \[\cos \theta -i\,\sin \theta \]
C. \[\cos \theta \pm i\,\sin \theta \]
D. \[\sin \theta \pm i\,\cos \theta \]
Answer» D. \[\sin \theta \pm i\,\cos \theta \]
4230.

The value of \[{{i}^{1+3+5+...+(2n+1)}}\] is [AMU 1999]

A. i if n is even, - i if n is odd
B. 1 if n is even, - 1 if n is odd
C. 1 if n is odd, - 1 if n is even
D. i if n is even, - 1 if n is odd
Answer» D. i if n is even, - 1 if n is odd
4231.

The least positive integer \[n\] which will reduce \[{{\left( \frac{i-1}{i+1} \right)}^{n}}\] to a real number, is [Roorkee 1998]

A. 2
B. 3
C. 4
D. 5
Answer» B. 3
4232.

The value of the sum \[\sum\limits_{n=1}^{13}{({{i}^{n}}+{{i}^{n+1}})}\], where \[i=\sqrt{-1}\], equals [IIT 1998]

A. \[i\]
B. \[i-1\]
C. \[-i\]
D. 0
Answer» C. \[-i\]
4233.

If \[{{i}^{2}}=-1\],  then the value of  \[\sum\limits_{n=1}^{200}{{{i}^{n}}}\]is [MP PET 1996]

A. \[50\]
B. -50
C. 0
D. 100
Answer» D. 100
4234.

If \[i=\sqrt{-1}\], then \[1+{{i}^{2}}+{{i}^{3}}-{{i}^{6}}+{{i}^{8}}\] is equal to [RPET 1995]

A. \[2-i\]
B. 1
C. 3
D. \[-1\]
Answer» B. 1
4235.

\[{{i}^{2}}+{{i}^{4}}+{{i}^{6}}+......\]upto \[(2n+1)\] terms = [EAMCET 1980; Kerala (Engg.) 2005]

A. \[i\]
B. \[-i\]
C. 1
D. \[-1\]
Answer» E.
4236.

\[\sqrt{-2}\,\sqrt{-3}=\] [Roorkee 1978]

A. \[\sqrt{6}\]
B. \[-\sqrt{6}\]
C. \[i\sqrt{6}\]
D. None of these
Answer» C. \[i\sqrt{6}\]
4237.

The function \[\sin x-bx+c\]will be increasing in the interval \[(-\infty ,\,\,\infty )\], if

A.            \[b\le 1\]
B.            \[b\le 0\]
C.            \[b<-1\]
D.            \[b\ge 0\]
Answer» D.            \[b\ge 0\]
4238.

The function \[\sin x-\cos x\]is increasing in the interval

A.            \[\left[ \frac{3\pi }{4},\frac{7\pi }{4} \right]\]
B.            \[\left[ 0,\frac{3\pi }{4} \right)\]
C.            \[\left[ \frac{\pi }{4},\frac{3\pi }{4} \right]\]
D.            None of these
Answer» C.            \[\left[ \frac{\pi }{4},\frac{3\pi }{4} \right]\]
4239.

A function is matched below against an interval where it is supposed to be increasing. Which of the following pairs is incorrectly matched? [AIEEE 2005]   

A.               Interval                                        Function             \[\left( -\infty ,\,\frac{1}{3} \right]\]                                                   \[3{{x}^{2}}-2x+1\]
B.             (? ¥, ? 4]                                         \[{{x}^{3}}+6{{x}^{2}}+6\]
C.             (? ¥, ¥)                                           \[{{x}^{3}}-3{{x}^{2}}+3x+3\]
D.                 [2, ¥)                                           \[2{{x}^{3}}-3{{x}^{2}}-12x+6\]
Answer» B.             (? ¥, ? 4]                                         \[{{x}^{3}}+6{{x}^{2}}+6\]
4240.

On the interval \[\left( 0,\frac{\pi }{2} \right)\], the function log sin x is

A.            Increasing                             
B.            Decreasing
C.            Neither increasing nor decreasing
D.            None of these
Answer» B.            Decreasing
4241.

Function \[f(x)=\frac{4{{x}^{2}}+1}{x}\] is decreasing for interval

A.            \[\left( \frac{-1}{2},\,\frac{1}{2} \right)\]
B.            \[\left[ \frac{1}{2},\,-\frac{1}{2} \right]\]
C.            (? 1, 1)
D.            [1, ?1]
Answer» C.            (? 1, 1)
4242.

Given function \[f(x)=\left( \frac{{{e}^{2x}}-1}{{{e}^{2x}}+1} \right)\] is [Orissa JEE 2005]

A.            Increasing
B.            Decreasing
C.            Even
D.            None of these
Answer» B.            Decreasing
4243.

The function \[f(x)={{\tan }^{-1}}(\sin x+\cos x)\], \[x>0\] is always an increasing function on the interval                         [Kerala (Engg.) 2005]

A.            \[(0,\,\pi )\]
B.            \[(0,\,\pi /2)\]
C.            \[(0,\pi /4)\]
D.            \[(0,\,3\pi /4)\]
E.            \[(0,\,5\pi /4)\]
Answer» D.            \[(0,\,3\pi /4)\]
4244.

The function \[f(x)=2{{x}^{3}}-3{{x}^{2}}+90x+174\] is increasing in the interval [J & K 2005]

A.            \[\frac{1}{2}<x<1\]
B.            \[\frac{1}{2}<x<2\]
C.            \[3<x<\frac{59}{4}\]
D.            \[-\infty <x<\infty \]
Answer» E.
4245.

If \[f(x)=x,-1\le x\le 1\], then function \[f(x)\] is                                                                               [SCRA 1996]

A.            Increasing
B.            Decreasing
C.            Stationary
D.            Discontinuous
Answer» B.            Decreasing
4246.

For all \[x\in (0,\,1)\] [IIT Screening 2000]

A.            \[{{e}^{x}}<1+x\]
B.            \[{{\log }_{e}}(1+x)<x\]
C.            \[\sin x>x\]
D.            \[{{\log }_{e}}x>x\]
Answer» C.            \[\sin x>x\]
4247.

The length of the longest interval, in which the function \[3\sin x-4\sin x\] is increasing, is                            [IIT Screening 2002]

A.            \[\frac{\pi }{3}\]
B.            \[\frac{\pi }{2}\]
C.            \[\frac{3\pi }{2}\]
D.            \[\pi \]
Answer» B.            \[\frac{\pi }{2}\]
4248.

The interval in which the function \[{{x}^{2}}{{e}^{-x}}\]is non decreasing, is

A.            \[(-\infty ,\,\,2]\]
B.            [0, 2]
C.            \[[2,\,\,\infty )\]
D.            None of these
Answer» C.            \[[2,\,\,\infty )\]
4249.

\[2{{x}^{3}}-6x+5\] is an increasing function if [UPSEAT 2003]

A.            \[0<x<1\]
B.            \[-1<x<1\]
C.            \[x<-1\] or \[x>1\]
D.            \[-1<x<-1/2\]
Answer» D.            \[-1<x<-1/2\]
4250.

The function                                                                            \[f(x)=1-{{x}^{3}}-{{x}^{5}}\]  is decreasing for  [Kerala (Engg.) 2002]

A.            \[1\le x\le 5\]
B.            \[x\le 1\]
C.            \[x\ge 1\]
D.            All values of x
Answer» E.