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.

6501.

\[\underset{x\to 1}{\mathop{\lim }}\,(1-x)\tan \left( \frac{\pi x}{2} \right)=\]  [IIT 1978, 84; RPET 1997, 2001;            UPSEAT 2003; Pb. CET 2003]

A. \[\frac{\pi }{2}\]
B. \[\pi \]
C. \[\frac{2}{\pi }\]
D. 0
Answer» D. 0
6502.

P is a fixed point \[(a,\,a,\,a)\] on a line through the origin equally inclined to the axes, then any plane through P perpendicular to OP, makes intercepts on the axes, the sum of whose reciprocals is equal to

A. a
B. \[\frac{3}{2a}\]
C. \[\frac{3a}{2}\]
D. None of these
Answer» E.
6503.

If \[\mathbf{a}\times \mathbf{r}=\mathbf{b}+\lambda \mathbf{a}\] and \[\mathbf{a}\,\,.\,\,\mathbf{r}=3,\] where \[\mathbf{a}=2\mathbf{i}+\mathbf{j}-\mathbf{k}\] and \[\mathbf{b}=-\mathbf{i}-2\mathbf{j}+\mathbf{k},\] then r and l are equal to 

A. \[\mathbf{r}=\frac{7}{6}\mathbf{i}+\frac{2}{3}\mathbf{j},\,\,\lambda =\frac{6}{5}\]
B. \[\mathbf{r}=\frac{7}{6}\mathbf{i}+\frac{2}{3}\mathbf{j},\,\,\lambda =\frac{5}{6}\]
C. \[\mathbf{r}=\frac{6}{7}\mathbf{i}+\frac{2}{3}\mathbf{j},\,\,\lambda =\frac{6}{5}\]
D. None of these
Answer» C. \[\mathbf{r}=\frac{6}{7}\mathbf{i}+\frac{2}{3}\mathbf{j},\,\,\lambda =\frac{6}{5}\]
6504.

If the straight line through the point \[P(3,\,4)\]makes an angle \[\frac{\pi }{6}\]with the x-axis and meets the line \[12x+5y+10=0\] at Q, then the length \[PQ\]is

A.            \[\frac{132}{12\sqrt{3}+5}\]    
B.            \[\frac{132}{12\sqrt{3}-5}\]
C.            \[\frac{132}{5\sqrt{3}+12}\]    
D.            \[\frac{132}{5\sqrt{3}-12}\]
Answer» B.            \[\frac{132}{12\sqrt{3}-5}\]
6505.

\[\int_{{}}^{{}}{{{(\log x)}^{2}}\ dx=}\]  [IIT 1971, 77]

A. \[x{{(\log x)}^{2}}-2x\log x-2x+c\]
B. \[x{{(\log x)}^{2}}-2x\log x-x+c\]
C. \[x{{(\log x)}^{2}}-2x\log x+2x+c\]        
D. \[x{{(\log x)}^{2}}-2x\log x+x+c\]
Answer» D. \[x{{(\log x)}^{2}}-2x\log x+x+c\]
6506.

If \[x=\sin t\] and \[y=\sin pt\], then the value of  \[\left( 1-{{x}^{2}} \right)\frac{{{d}^{2}}y}{d{{x}^{2}}}-x\frac{dy}{dx}+{{p}^{2}}y\]is equal to [Pb. CET 2002]

A. 0
B. 1
C. -1
D. \[\sqrt{2}\]
Answer» B. 1
6507.

If \[f:R\to R\]and \[g:R\to R\] are defined by \[f(x)=2x+3\]and \[g(x)={{x}^{2}}+7\], then the values of x such that \[g(f(x))=8\] are [EAMCET 2000, 03]

A. 1, 2
B. -1, 2
C. -1, -2
D. 1, -2
Answer» D. 1, -2
6508.

A variable plane at a constant distance p from origin meets the co-ordinates axes in \[A,B,C\]. Through these points planes are drawn parallel to co-ordinate planes. Then locus of the point of intersection is

A. \[\frac{1}{{{x}^{2}}}+\frac{1}{{{y}^{2}}}+\frac{1}{{{z}^{2}}}=\frac{1}{{{p}^{2}}}\]
B. \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}={{p}^{2}}\]
C. \[x+y+z=p\]
D. \[\frac{1}{x}+\frac{1}{y}+\frac{1}{z}=p\]
Answer» B. \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}={{p}^{2}}\]
6509.

If \[\mathbf{a}=2\mathbf{i}+\mathbf{k},\,\,\mathbf{b}=\mathbf{i}+\mathbf{j}+\mathbf{k}\] and \[\mathbf{c}=4\mathbf{i}-3\mathbf{j}+7\mathbf{k}.\] If \[\mathbf{d}\times \mathbf{b}=\mathbf{c}\times \mathbf{b}\] and \[\mathbf{d}\,.\,\mathbf{a}=0,\] then d will be [IIT 1990]

A. \[\mathbf{i}+8\mathbf{j}+2\mathbf{k}\]
B. \[\mathbf{i}-8\mathbf{j}+2\mathbf{k}\]
C. \[-\mathbf{i}+8\mathbf{j}-\mathbf{k}\]
D. \[-\mathbf{i}-8\mathbf{j}+2\mathbf{k}\]
Answer» E.
6510.

In \[\Delta ABC,\ \frac{1}{a}{{\cos }^{2}}\frac{A}{2}+\frac{1}{b}{{\cos }^{2}}\frac{B}{2}+\frac{1}{c}{{\cos }^{2}}\frac{C}{2}=\]

A. \[s\]
B. \[\frac{s}{abc}\]
C. \[\frac{{{s}^{2}}}{abc}\]
D. \[\frac{{{s}^{3}}}{abc}\]
Answer» D. \[\frac{{{s}^{3}}}{abc}\]
6511.

Given vertices \[A(1,\,1),B(4,\,-2)\]and \[C(5,\,5)\]of a triangle, then the equation of the perpendicular dropped from C to the interior bisector of the angle A is                                              [Roorkee 1994]

A.            \[y-5=0\]                                   
B.            \[x-5=0\]
C.            \[y+5=0\]                                  
D.            \[x+5=0\]
Answer» C.            \[y+5=0\]                                  
6512.

The lines joining the origin to the points of intersection of the line \[y=mx+c\]and the circle \[{{x}^{2}}+{{y}^{2}}={{a}^{2}}\]will be mutually perpendicular, if                                             [Roorkee 1977]

A.            \[{{a}^{2}}({{m}^{2}}+1)={{c}^{2}}\]                              
B.            \[{{a}^{2}}({{m}^{2}}-1)={{c}^{2}}\]
C.            \[{{a}^{2}}({{m}^{2}}+1)={{c}^{2}}\]                              
D.            \[{{a}^{2}}({{m}^{2}}-1)=2{{c}^{2}}\]
Answer» D.            \[{{a}^{2}}({{m}^{2}}-1)=2{{c}^{2}}\]
6513.

If one of the lines of the pair \[a{{x}^{2}}+2hxy+b{{y}^{2}}=0\] bisects the angle between positive directions of the axes, then a, b, h satisfy the relation                           [Roorkee 1992]

A.            \[a+b=2|h|\]                       
B.            \[a+b=-2h\]
C.            \[a-b=2|h|\]                        
D.            \[{{(a-b)}^{2}}=4{{h}^{2}}\]
Answer» C.            \[a-b=2|h|\]                        
6514.

If integrating factor of \[x(1-{{x}^{2}})dy+(2{{x}^{2}}y-y-a{{x}^{3}})dx=0\] is \[{{e}^{\int_{{}}^{{}}{Pdx}}},\] then P is equal to [MP PET 1999]

A. \[\frac{2{{x}^{2}}-a{{x}^{3}}}{x(1-{{x}^{2}})}\]       
B. \[(2{{x}^{2}}-1)\]
C. \[\frac{2{{x}^{2}}-1}{a{{x}^{3}}}\]                                 
D. \[\frac{(2{{x}^{2}}-1)}{x(1-{{x}^{2}})}\]
Answer» E.
6515.

\[\int_{{}}^{{}}{\frac{{{x}^{2}}+1}{{{x}^{4}}-{{x}^{2}}+1}\ dx=}\]         [MP PET 1991]

A. \[{{\tan }^{-1}}\left( \frac{1+{{x}^{2}}}{x} \right)+c\]
B. \[{{\cot }^{-1}}\left( \frac{1+{{x}^{2}}}{x} \right)+c\]
C. \[{{\tan }^{-1}}\left( \frac{{{x}^{2}}-1}{x} \right)+c\]
D. \[{{\cot }^{-1}}\left( \frac{{{x}^{2}}-1}{x} \right)+c\]
Answer» D. \[{{\cot }^{-1}}\left( \frac{{{x}^{2}}-1}{x} \right)+c\]
6516.

If \[f(x)=3x+10\], \[g(x)={{x}^{2}}-1\], then \[{{(fog)}^{-1}}\] is equal to                     [UPSEAT 2001]

A. \[{{\left( \frac{x-7}{3} \right)}^{1/2}}\]
B. \[{{\left( \frac{x+7}{3} \right)}^{1/2}}\]
C. \[{{\left( \frac{x-3}{7} \right)}^{1/2}}\]
D. \[{{\left( \frac{x+3}{7} \right)}^{1/2}}\]
Answer» B. \[{{\left( \frac{x+7}{3} \right)}^{1/2}}\]
6517.

Two middle terms in the expansion of \[{{\left( x-\frac{1}{x} \right)}^{11}}\] are

A. 231x and \[\frac{231}{x}\]
B. \[462x\] and \[\frac{462}{x}\]
C. \[-462x\] and \[\frac{462}{x}\]
D. None of these
Answer» D. None of these
6518.

AB is a vertical tower. The point A is on the ground and C is the middle point of AB. The part CB subtend an angle \[\alpha \]at a point P on the ground. If \[AP=n\,AB,\]then the correct relation is  [MNR 1989; IIT 1980]

A. \[n=({{n}^{2}}+1)\tan \alpha \]
B. \[n=(2{{n}^{2}}-1)\tan \alpha \]
C. \[{{n}^{2}}=(2{{n}^{2}}+1)\tan \alpha \]
D. \[n=(2{{n}^{2}}+1)\tan \alpha \]
Answer» E.
6519.

\[2{{\tan }^{-1}}(\cos x)={{\tan }^{-1}}(\text{cose}{{\text{c}}^{2}}x),\] then x = [UPSEAT 2002]

A. \[\frac{\pi }{2}\]
B. \[\pi \]
C. \[\frac{\pi }{6}\]
D. \[\frac{\pi }{3}\]
Answer» E.
6520.

The sides \[AB,BC,CD\] and \[DA\]of a quadrilateral are \[x+2y=3,\,x=1,\] \[x-3y=4,\,\] \[\,5x+y+12=0\] respectively.  The angle between diagonals \[AC\]and \[BD\]is  [Roorkee 1993]

A.            \[{{45}^{o}}\]                            
B.            \[{{60}^{o}}\]
C.            \[{{90}^{o}}\]                            
D.            \[{{30}^{o}}\]
Answer» D.            \[{{30}^{o}}\]
6521.

The solution of the given differential equation \[\frac{dy}{dx}+2xy=y\] is [Roorkee 1995]

A. \[y=c{{e}^{x-{{x}^{2}}}}\]    
B. \[y=c{{e}^{{{x}^{2}}-x}}\]
C. \[y=c{{e}^{x}}\]                  
D. \[y=c{{e}^{-{{x}^{2}}}}\]
Answer» B. \[y=c{{e}^{{{x}^{2}}-x}}\]
6522.

\[\int_{{}}^{{}}{\frac{dx}{4{{\sin }^{2}}x+5{{\cos }^{2}}x}=}\]              [AISSE 1986]

A. \[\frac{1}{\sqrt{5}}{{\tan }^{-1}}\left( \frac{2\tan x}{\sqrt{5}} \right)+c\]
B. \[\frac{1}{\sqrt{5}}{{\tan }^{-1}}\left( \frac{\tan x}{\sqrt{5}} \right)+c\]
C. \[\frac{1}{2\sqrt{5}}{{\tan }^{-1}}\left( \frac{2\tan x}{\sqrt{5}} \right)+c\]
D. None of these
Answer» D. None of these
6523.

Let \[f(x)\]and \[g(x)\]be two functions having finite non-zero 3rd order derivatives \[{f}'''(x)\]and \[{g}'''(x)\] for all, \[x\in R\]. If \[f(x)g(x)=1\]for all \[x\in R\], then \[\frac{{{f}'''}}{{{f}'}}-\frac{{{g}'''}}{{{g}'}}\]is equal to

A. \[3\text{ }\left( \frac{{{f}''}}{g}-\frac{{{g}''}}{f} \right)\]
B. \[3\text{ }\left( \frac{{{f}''}}{f}-\frac{{{g}''}}{g} \right)\]
C. \[3\text{ }\left( \frac{g''}{g}-\frac{f''}{g} \right)\]
D. \[3\text{ }\left( \frac{{{f}''}}{f}-\frac{{{g}''}}{f} \right)\]
Answer» C. \[3\text{ }\left( \frac{g''}{g}-\frac{f''}{g} \right)\]
6524.

If \[g(f(x))=|\sin x|\] and \[f(g(x))={{(\sin \sqrt{x})}^{2}}\], then                 [IIT 1998]

A. \[f(x)={{\sin }^{2}}x,\ g(x)=\sqrt{x}\]                                           
B. \[f(x)=\sin x,\ g(x)=|x|\]
C. \[f(x)={{x}^{2}},\ g(x)=\sin \sqrt{x}\]                                           
D. f and g cannot be determined
Answer» B. \[f(x)=\sin x,\ g(x)=|x|\]
6525.

Let R be a relation on the set N be defined by {(x, y)| x, y \[\overset{\hat{\ }}{\mathop{i}}\,\]N, 2x + y = 41}. Then R is

A. Reflexive
B. Symmetric
C. Transitive
D. None of these
Answer» E.
6526.

Middle term in the expansion of \[{{(1+3x+3{{x}^{2}}+{{x}^{3}})}^{6}}\]is [MP PET 1997]

A. \[{{4}^{th}}\]
B. \[{{3}^{rd}}\]
C. \[{{10}^{th}}\]
D. None of these
Answer» D. None of these
6527.

The equation \[{{x}^{2}}-3xy+\lambda {{y}^{2}}+3x-5y+2=0\] when \[\lambda \]is a real number, represents a pair of straight lines. If \[\theta \] is the angle between the lines, then \[\text{cose}{{\text{c}}^{2}}\theta \]= [EAMCET 1992]

A.            3    
B.            9
C.            10  
D.            100
Answer» D.            100
6528.

The solution of the equation \[\frac{dy}{dx}=\frac{1}{x+y+1}\] is

A. \[x=c{{e}^{y}}-y-2\]           
B. \[y=x+c{{e}^{y}}-2\]
C. \[x+c{{e}^{y}}-y-2=0\]      
D. None of these
Answer» B. \[y=x+c{{e}^{y}}-2\]
6529.

If \[\int_{{}}^{{}}{f(x)\sin x\cos x\ dx=\frac{1}{2({{b}^{2}}-{{a}^{2}})}\log (f(x))}+c\], then \[f(x)=\]

A. \[\frac{1}{{{a}^{2}}{{\sin }^{2}}x+{{b}^{2}}{{\cos }^{2}}x}\]
B. \[\frac{1}{{{a}^{2}}{{\sin }^{2}}x-{{b}^{2}}{{\cos }^{2}}x}\]
C. \[\frac{1}{{{a}^{2}}{{\cos }^{2}}x+{{b}^{2}}{{\sin }^{2}}x}\]
D. \[\frac{1}{{{a}^{2}}{{\cos }^{2}}x-{{b}^{2}}{{\sin }^{2}}x}\]
Answer» B. \[\frac{1}{{{a}^{2}}{{\sin }^{2}}x-{{b}^{2}}{{\cos }^{2}}x}\]
6530.

If \[{{y}^{2}}=p(x)\]is a polynomial of degree three, then \[2\frac{d}{dx}\left\{ {{y}^{3}}.\frac{{{d}^{2}}y}{d{{x}^{2}}} \right\}\]= [IIT 1988; RPET 2000]

A. \[{p}'''(x)+p'(x)\]
B. \[{p}''(x).{p}'''(x)\]
C. \[p(x).{p}'''(x)\]
D. Constant
Answer» D. Constant
6531.

If \[f(x)={{\sin }^{2}}x+{{\sin }^{2}}\left( x+\frac{\pi }{3} \right)+\cos x\cos \left( x+\frac{\pi }{3} \right)\] and \[g\left( \frac{5}{4} \right)=1\], then \[(gof)(x)=\] [IIT 1996]

A. -2
B. -1
C. 2
D. 1
Answer» E.
6532.

Let a relation R be defined by R = {(4, 5); (1, 4); (4, 6);     (7, 6); (3, 7)} then \[{{R}^{-1}}oR\] is

A. {(1, 1), (4, 4), (4, 7), (7, 4), (7, 7), (3, 3)}
B. {(1, 1), (4, 4), (7, 7), (3, 3)}
C. {(1, 5), (1, 6), (3, 6)}
D. None of these
Answer» B. {(1, 1), (4, 4), (7, 7), (3, 3)}
6533.

The value of \[\left( \begin{matrix}   30  \\   0  \\\end{matrix} \right)\left( \begin{matrix}   30  \\   10  \\\end{matrix} \right)-\left( \begin{matrix}   30  \\   1  \\\end{matrix} \right)\left( \begin{matrix}   30  \\   11  \\\end{matrix} \right)+\left( \begin{matrix}   30  \\   2  \\\end{matrix} \right)\left( \begin{matrix}   30  \\   12  \\\end{matrix} \right)+......+\left( \begin{matrix}   30  \\   20  \\\end{matrix} \right)\left( \begin{matrix}   30  \\   30  \\\end{matrix} \right)\][IIT Screening 2005]

A. \[^{60}{{C}_{20}}\]
B. \[^{30}{{C}_{10}}\]
C. \[^{60}{{C}_{30}}\]
D. \[^{40}{{C}_{30}}\]
Answer» C. \[^{60}{{C}_{30}}\]
6534.

Two fixed points are \[A(a,0)\]and\[B(-a,0)\]. If\[\angle A-\angle B=\theta \], then the locus of point C of triangle ABC will be      [Roorkee 1982]

A. \[{{x}^{2}}+{{y}^{2}}+2xy\tan \theta ={{a}^{2}}\]
B. \[{{x}^{2}}-{{y}^{2}}+2xy\tan \theta ={{a}^{2}}\]
C. \[{{x}^{2}}+{{y}^{2}}+2xy\cot \theta ={{a}^{2}}\]
D. \[{{x}^{2}}-{{y}^{2}}+2xy\cot \theta ={{a}^{2}}\]
Answer» E.
6535.

\[2{{\tan }^{-1}}\left[ \sqrt{\frac{a-b}{a+b}}\tan \frac{\theta }{2} \right]=\]  [Dhanbad Engg. 1976]

A. \[{{\cos }^{-1}}\left( \frac{a\cos \theta +b}{a+b\cos \theta } \right)\]
B. \[{{\cos }^{-1}}\left( \frac{a+b\cos \theta }{a\cos \theta +b} \right)\]
C. \[{{\cos }^{-1}}\left( \frac{a\cos \theta }{a+b\cos \theta } \right)\]
D. \[{{\cos }^{-1}}\left( \frac{a\cos +b\theta }{a+b\cos \theta } \right)\]
Answer» B. \[{{\cos }^{-1}}\left( \frac{a+b\cos \theta }{a\cos \theta +b} \right)\]
6536.

In what direction a line be drawn through the point (1, 2) so that its points of intersection with the line \[x+y=4\] is at a distance \[\frac{\sqrt{6}}{3}\] from the given point                             [IIT 1966; MNR 1987]

A.            \[{{30}^{o}}\]                            
B.            \[{{45}^{o}}\]
C.            \[{{60}^{o}}\]                            
D.            \[{{75}^{o}}\]
Answer» E.
6537.

The figure formed by the lines \[{{x}^{2}}+4xy+{{y}^{2}}=0\] and \[x-y=4,\] is                                     [Roorkee 1980]

A.            A right angled triangle      
B.            An isosceles triangle
C.            An equilateral triangle     
D.            None of these
Answer» D.            None of these
6538.

\[\int_{{}}^{{}}{x\sqrt{\frac{1-{{x}^{2}}}{1+{{x}^{2}}}}}\ dx=\]

A. \[\frac{1}{2}[{{\sin }^{-1}}{{x}^{2}}+\sqrt{1-{{x}^{4}}}]+c\] 
B. \[\frac{1}{2}[{{\sin }^{-1}}{{x}^{2}}+\sqrt{1-{{x}^{2}}}]+c\]
C. \[{{\sin }^{-1}}{{x}^{2}}+\sqrt{1-{{x}^{4}}}+c\]     
D. \[{{\sin }^{-1}}{{x}^{2}}+\sqrt{1-{{x}^{2}}}+c\]
Answer» B. \[\frac{1}{2}[{{\sin }^{-1}}{{x}^{2}}+\sqrt{1-{{x}^{2}}}]+c\]
6539.

If f is an even function defined on the interval (-5, 5), then four real values of x satisfying the equation  \[f(x)=f\left( \frac{x+1}{x+2} \right)\]  are [IIT 1996]

A. \[\frac{-3-\sqrt{5}}{2},\ \frac{-3+\sqrt{5}}{2},\ \frac{3-\sqrt{5}}{2},\ \frac{3+\sqrt{5}}{2}\]
B. \[\frac{-5+\sqrt{3}}{2},\ \frac{-3+\sqrt{5}}{2},\ \frac{3+\sqrt{5}}{2},\ \frac{3-\sqrt{5}}{2}\]
C. \[\frac{3-\sqrt{5}}{2},\ \frac{3+\sqrt{5}}{2},\ \frac{-3-\sqrt{5}}{2},\ \frac{5+\sqrt{3}}{2}\]
D. \[-3-\sqrt{5},\ -3+\sqrt{5},\ 3-\sqrt{5},\ 3+\sqrt{5}\]
Answer» B. \[\frac{-5+\sqrt{3}}{2},\ \frac{-3+\sqrt{5}}{2},\ \frac{3+\sqrt{5}}{2},\ \frac{3-\sqrt{5}}{2}\]
6540.

A line with direction cosines proportional to 2,1, 2 meets each of the lines \[x=y+a=z\]and \[x+a=2y=2z\]. The co-ordinates of each of the points of intersection are given by [AIEEE 2004]

A. \[(2a,\,\,a,\,3a),(2a,\,a,\,a)\]
B. \[(3a,\,2a,\,3a),\ (a,\,a,\,a)\]
C. \[(3a,\,2a,\,3a),(a,\,a,\,2a)\]
D. \[(3a,\,3a,\,3a),(a,\,a,\,a)\]
Answer» C. \[(3a,\,2a,\,3a),(a,\,a,\,2a)\]
6541.

Let \[\mathbf{b}=4\mathbf{i}+3\mathbf{j}\] and c be two vectors perpendicular to each other in the xy-plane. All vectors in the same plane having projections 1 and 2 along b and c respectively, are given by [IIT 1987]

A. \[2\mathbf{i}-\mathbf{j},\,\,\frac{2}{5}\mathbf{i}+\frac{11}{5}\mathbf{j}\]
B. \[2\mathbf{i}+\mathbf{j},\,\,-\frac{2}{5}\mathbf{i}+\frac{11}{5}\mathbf{j}\]
C. \[2\mathbf{i}+\mathbf{j},\,-\frac{2}{5}\mathbf{i}-\frac{11}{5}\mathbf{j}\]
D. \[2\mathbf{i}-\mathbf{j},\,\,-\frac{2}{5}\mathbf{i}+\frac{11}{5}\mathbf{j}\]
Answer» E.
6542.

Let R and S be two non-void relations on a set A. Which of the following statements is false

A. R and S are transitive \[\Rightarrow \text{ }R\text{ }\cup \text{ }S\] is transitive
B. R and S are transitive \[\Rightarrow \text{ }R\text{ }\cap \text{ }S\] is transitive
C. R and S are symmetric \[\Rightarrow \text{ }R\text{ }\cup \text{ }S\] is symmetric
D. R and S are reflexive \[\Rightarrow \text{ }R\text{ }\cap \text{ }S\] is reflexive
Answer» B. R and S are transitive \[\Rightarrow \text{ }R\text{ }\cap \text{ }S\] is transitive
6543.

The number of solution of the given equation \[a\sin x+b\cos x=c\] ,  where \[|c|\,>\,\sqrt{{{a}^{2}}+{{b}^{2}}},\]is [DCE 1998]

A. 1
B. 2
C. Infinite
D. None of these
Answer» E.
6544.

If \[{{\tan }^{-1}}x+{{\tan }^{-1}}y+{{\tan }^{-1}}z=\pi \], then \[x+y+z\] is equal to  [Kerala (Engg.) 2002]

A. xyz
B. 0
C. 1
D. 2xyz
Answer» B. 0
6545.

A line \[4x+y=1\]passes through the point \[A(2,\ -\ 7)\] meets the line BC whose equation is \[3x-4y+1=0\] at the point B. The equation to the line AC so that AB = AC, is                                [IIT 1971]

A.            \[52x+89y+519=0\]                   
B.            \[\beta \]
C.            \[89x+52y+519=0\]                   
D.            \[89x+52y-519=0\]
Answer» B.            \[\beta \]
6546.

The pair of lines represented by \[3a{{x}^{2}}+5xy+({{a}^{2}}-2){{y}^{2}}=0\] are perpendicular to each other for   [AIEEE 2002]

A.            Two values of \[a\]           
B.            \[\forall a\]
C.            For one value of \[a\]      
D.            For no value of \[a\]
Answer» B.            \[\forall a\]
6547.

Let \[f(x)={{(x+1)}^{2}}-1,\ \ (x\ge -1)\]. Then the set \[S=\{x:f(x)={{f}^{-1}}(x)\}\] is                           [IIT 1995]

A. Empty
B. {0, -1}
C. {0, 1, -1}
D. \[\left\{ 0,\ -1,\ \frac{-3+i\sqrt{3}}{2},\ \frac{-3-i\sqrt{3}}{2} \right\}\]
Answer» E.
6548.

A square \[ABCD\] of diagonal 2a is folded along the diagonal \[AC\] so that the planes \[DAC\] and \[BAC\] are at right angle. The shortest distance between \[DC\] and \[AB\] is [Kurukshetra CEE 1998]

A. \[\sqrt{2}a\]
B. \[2a/\sqrt{3}\]
C. \[2a/\sqrt{5}\]
D. [(\sqrt{3}/2)a\]
Answer» C. \[2a/\sqrt{5}\]
6549.

If \[\overrightarrow{A}=\mathbf{i}+2\mathbf{j}+3\mathbf{k},\,\,\,\overrightarrow{B}=-\mathbf{i}+2\mathbf{j}+\mathbf{k}\] and \[\overrightarrow{C}=3\mathbf{i}+\mathbf{j},\] then the value of t such that \[\overrightarrow{A}+t\overrightarrow{B}\] is at right angle to vector \[3\mathbf{i}+4\mathbf{j}\] is       [RPET 2002]

A. 2
B. 4
C. 5
D. 6
Answer» D. 6
6550.

Let R be a relation on the set N of natural numbers defined by nRm \[\Leftrightarrow \] n is a factor of m (i.e., n|m). Then R is

A. Reflexive and symmetric
B. Transitive and symmetric
C. Equivalence
D. Reflexive, transitive but not symmetric
Answer» E.