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.

1801.

In a triangle \[ABC\], \[\frac{2\cos A}{a}+\frac{\cos B}{b}+\frac{2\cos C}{c}=\] \[\frac{a}{bc}+\frac{b}{ca}\], then the value of angle A is [IIT 1993]

A. \[{{45}^{o}}\]
B. \[{{30}^{o}}\]
C. \[{{90}^{o}}\]
D. \[{{60}^{o}}\]
Answer» D. \[{{60}^{o}}\]
1802.

If the angles of a triangle are in the ratio 1: 2: 3, then their corresponding sides are in the ratio [MP PET 1993; BIT Ranchi 1992; Pb. CET 1990]

A. 0.0430902777777778
B. \[1:\sqrt{3}:2\]
C. \[\sqrt{2}:\sqrt{3}:3\]
D. \[1:\sqrt{3}:3\]
Answer» C. \[\sqrt{2}:\sqrt{3}:3\]
1803.

If the sides of a triangle are in A. P., then the cotangent of its half the angles will be in  [MP PET 1993]

A. H. P.
B. G. P.
C. A. P.
D. No particular order
Answer» D. No particular order
1804.

If in \[\Delta \,ABC\], \[2{{b}^{2}}={{a}^{2}}+{{c}^{2}},\]then \[\frac{\sin 3B}{\sin B}=\] [UPSEAT 1999]

A. \[\frac{{{c}^{2}}-{{a}^{2}}}{2ca}\]
B. \[\frac{{{c}^{2}}-{{a}^{2}}}{ca}\]
C. \[{{\left( \frac{{{c}^{2}}-{{a}^{2}}}{ca} \right)}^{2}}\]
D. \[{{\left( \frac{{{c}^{2}}-{{a}^{2}}}{2ca} \right)}^{2}}\]
Answer» E.
1805.

In\[\Delta \,ABC\],\[({{b}^{2}}-{{c}^{2}})\cot A+({{c}^{2}}-{{a}^{2}})\cot B+({{a}^{2}}-{{b}^{2}})\cot C=\]

A. 0
B. \[{{a}^{2}}+{{b}^{2}}+{{c}^{2}}\]
C. \[2\,({{a}^{2}}+{{b}^{2}}+{{c}^{2}})\]
D. \[\frac{1}{2abc}\]
Answer» B. \[{{a}^{2}}+{{b}^{2}}+{{c}^{2}}\]
1806.

In \[\Delta \,ABC\], \[\frac{\cos \frac{1}{2}(B-C)}{\sin \frac{1}{2}A}=\]   [MP PET 1993; Roorkee 1973]

A. \[\frac{b-c}{a}\]
B. \[\frac{b+c}{a}\]
C. \[\frac{a}{b-c}\]
D. \[\frac{a}{b+c}\]
Answer» C. \[\frac{a}{b-c}\]
1807.

If the angles of a triangle \[ABC\]be in A.P., then

A. \[{{c}^{2}}={{a}^{2}}+{{b}^{2}}-ab\]
B. \[{{b}^{2}}={{a}^{2}}+{{c}^{2}}-ac\]
C. \[{{a}^{2}}={{b}^{2}}+{{c}^{2}}-ac\]
D. \[{{b}^{2}}={{a}^{2}}+{{c}^{2}}\]
Answer» C. \[{{a}^{2}}={{b}^{2}}+{{c}^{2}}-ac\]
1808.

In triangle \[ABC,\]\[\frac{1+\cos (A-B)\cos C}{1+\cos (A-C)\cos B}=\]

A. \[\frac{a-b}{a-c}\]
B. \[\frac{a+b}{a+c}\]
C. \[\frac{{{a}^{2}}-{{b}^{2}}}{{{a}^{2}}-{{c}^{2}}}\]
D. \[\frac{{{a}^{2}}+{{b}^{2}}}{{{a}^{2}}+{{c}^{2}}}\]
Answer» E.
1809.

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

A. \[\frac{{{a}^{2}}+{{b}^{2}}+{{c}^{2}}}{abc}\]
B. \[\frac{{{a}^{2}}+{{b}^{2}}+{{c}^{2}}}{2abc}\]
C. \[\frac{2({{a}^{2}}+{{b}^{2}}+{{c}^{2}})}{abc}\]
D. \[{{a}^{2}}+{{b}^{2}}+{{c}^{2}}\]
Answer» C. \[\frac{2({{a}^{2}}+{{b}^{2}}+{{c}^{2}})}{abc}\]
1810.

In \[\Delta ABC\], \[c\cos (A-\alpha )+a\cos (C+\alpha )=\]

A. \[a\cos \alpha \]
B. \[b\cos \alpha \]
C. \[c\cos \alpha \]
D. \[2b\cos \alpha \]
Answer» C. \[c\cos \alpha \]
1811.

In \[\Delta ABC\], if \[\angle C={{90}^{o}}\],\[\angle A={{30}^{o}}\], \[c=20\], then the values of a and b are

A. 10, 10
B. \[10,\,10\sqrt{3}\]
C. \[5,\,\,5\sqrt{3}\]
D. \[8,\,\,8\sqrt{3}\]
Answer» C. \[5,\,\,5\sqrt{3}\]
1812.

In a \[\Delta ABC\],side b is equal to          [MP PET 1984,  92]

A. \[c\cos A+a\cos C\]
B. \[a\cos B+b\cos A\]
C. \[b\cos C+c\cos B\]
D. None of these
Answer» B. \[a\cos B+b\cos A\]
1813.

If the sides of a right angled triangle be in A. P. , then their ratio will be

A. 0.0430902777777778
B. 0.085462962962963
C. 0.127835648148148
D. 0.170208333333333
Answer» D. 0.170208333333333
1814.

If the lengths of the sides of a triangle be \[7,4\sqrt{3}\] and \[\sqrt{13}\]cm, then the smallest angle is [MNR 1985]

A. \[{{15}^{o}}\]
B. \[{{30}^{o}}\]
C. \[60{}^\circ \]
D. \[{{45}^{o}}\]
Answer» C. \[60{}^\circ \]
1815.

In a \[\Delta ABC\], if \[2s=a+b+c\]and \[(s-b)(s-c)=\] \[x{{\sin }^{2}}\frac{A}{2},\] then x = [MP PET 1992]

A. bc
B. ca
C. ab
D. abc
Answer» B. ca
1816.

If the sides of a triangle are in the ratio \[2:\sqrt{6}:(\sqrt{3}+1)\], then the largest angle of the triangle will be [MP PET 1990]

A. \[{{60}^{o}}\]
B. \[{{75}^{o}}\]
C. \[{{90}^{o}}\]
D. \[{{120}^{o}}\]
Answer» C. \[{{90}^{o}}\]
1817.

In \[\Delta ABC\], if \[a=3,b=4,c=5\], then \[\sin 2B=\]  [MP PET 1983]

A. 44320
B. 43891
C. 24/25
D. 18264
Answer» D. 18264
1818.

In triangle \[ABC\]if \[a,b,c\]are in A. P., then the value of \[\frac{\sin \frac{A}{2}\sin \frac{C}{2}}{\sin \frac{B}{2}}=\] [AMU 1995]

A. 1
B. 44228
C. 2
D. -1
Answer» C. 2
1819.

In \[\Delta ABC\], if \[\tan \frac{A}{2}\tan \frac{C}{2}=\frac{1}{2},\]then \[a,b,c\]are in

A. A. P.
B. G. P.
C. H. P.
D. None of these
Answer» E.
1820.

If the angles of a triangle be in the ratio 1 : 2 : 7, then the ratio of its greatest side to the least side is

A. \[1:2\]
B. 0.0840277777777778
C. \[(\sqrt{5}+1):(\sqrt{5}-1)\]
D. \[(\sqrt{5}-1):(\sqrt{5}+1)\]
Answer» D. \[(\sqrt{5}-1):(\sqrt{5}+1)\]
1821.

If \[{{\cos }^{2}}A+{{\cos }^{2}}C={{\sin }^{2}}B,\]then \[\Delta ABC\]is [MP PET 1991]

A. Equilateral
B. Right angled
C. Isosceles
D. None of these
Answer» C. Isosceles
1822.

In \[\Delta ABC,\] \[\text{cosec }A(\sin B\cos C+\cos B\sin C)=\] [MP PET 1986, 1995; Pb. CET 1990, 94]

A. \[c/a\]
B. \[a/c\]
C. 1
D. \[c/ab\]
Answer» D. \[c/ab\]
1823.

In\[\Delta ABC,\] if \[2(bc\cos A+ca\cos B+ab\cos C)=\]

A. 0
B. \[a+b+c\]
C. \[{{a}^{2}}+{{b}^{2}}+{{c}^{2}}\]
D. None of these
Answer» D. None of these
1824.

If in a triangle \[ABC,\]\[(s-a)(s-b)=s\,\,(s-c)\], then  angle C is equal to [MP PET 1986]

A. \[{{90}^{o}}\]
B. \[{{45}^{o}}\]
C. \[{{30}^{o}}\]
D. \[{{60}^{o}}\]
Answer» B. \[{{45}^{o}}\]
1825.

In \[\Delta ABC,\] if \[(a+b+c)(a-b+c)\]=3ac, then  [AMU 1996]

A. \[\angle B={{60}^{o}}\]
B. \[\angle B={{30}^{o}}\]
C. \[\angle C={{60}^{o}}\]
D. \[\angle A+\angle C={{90}^{o}}\]
Answer» B. \[\angle B={{30}^{o}}\]
1826.

In\[\Delta ABC,\]a\[\sin (B-C)+b\sin (C-A)+c\sin (A-B)=\] [ISM Dhanbad 1973]

A. 0
B. \[a+b+c\]
C. \[{{a}^{2}}+{{b}^{2}}+{{c}^{2}}\]
D. \[2({{a}^{2}}+{{b}^{2}}+{{c}^{2}})\]
Answer» B. \[a+b+c\]
1827.

In\[\Delta ABC,\]if \[\cot A,\cot B,\cot C\]be in A. P., then \[{{a}^{2}},\text{ }{{b}^{2}},\text{ }{{c}^{2}}\] are in [MP PET 1997]

A. H. P.
B. G. P.
C. A. P.
D. None of these
Answer» D. None of these
1828.

If in a triangle \[ABC,a=5,b=4,A=\frac{\pi }{2}+B\], then C   [Kerala (Engg.) 2005]

A. Is \[{{\tan }^{-1}}\left( \frac{1}{9} \right)\]
B. Is \[{{\tan }^{-1}}\frac{1}{40}\]
C. Cannot be evaluated
D. Is\[2{{\tan }^{-1}}\left( 1/9 \right)\]
E. Is \[2{{\tan }^{-1}}\frac{1}{40}\]
Answer» E. Is \[2{{\tan }^{-1}}\frac{1}{40}\]
1829.

\[ABC\] is a right angled isosceles triangle with \[\angle B={{90}^{o}}\]. If D is a point on \[AB\] so that \[\angle DCB={{15}^{o}}\] and if \[AD=35cm\], then \[CD=\] [Kerala (Engg.) 2005]

A.  \[35\sqrt{2}\]cm
B. \[70\sqrt{2}cm\]
C. \[\frac{35\sqrt{3}}{2}cm\]
D. \[35\sqrt{6}\]cm
E. \[\frac{35\sqrt{2}}{2}cm\]
Answer» B. \[70\sqrt{2}cm\]
1830.

Which of the following is true in a triangle ABC [IIT Screening 2005]

A. \[(b+c)\sin \frac{B-C}{2}=2a\cos \frac{A}{2}\]
B.  \[(b+c)\cos \frac{A}{2}=2a\sin \frac{B-C}{2}\]
C. \[(b-c)\cos \frac{A}{2}=a\sin \frac{B-C}{2}\]
D. \[(b-c)\sin \frac{B-C}{2}=2a\cos \frac{A}{2}\]
Answer» D. \[(b-c)\sin \frac{B-C}{2}=2a\cos \frac{A}{2}\]
1831.

If the line segment joining the points \[A(a,\,b)\] and \[B(c,\,d)\] subtends an angle \[\theta \] at the origin, then \[\cos \theta \] is equal to [IIT 1961]

A. \[\frac{ab+cd}{\sqrt{({{a}^{2}}+{{b}^{2}})\,({{c}^{2}}+{{d}^{2}})}}\]
B. \[\frac{ac+bd}{\sqrt{({{a}^{2}}+{{b}^{2}})\,({{c}^{2}}+{{d}^{2}})}}\]
C. \[\frac{ac-bd}{\sqrt{({{a}^{2}}+{{b}^{2}})\,({{c}^{2}}+{{d}^{2}})}}\]
D. None of these
Answer» C. \[\frac{ac-bd}{\sqrt{({{a}^{2}}+{{b}^{2}})\,({{c}^{2}}+{{d}^{2}})}}\]
1832.

If a, b and c are the sides of a triangle such that \[{{a}^{4}}+{{b}^{4}}+{{c}^{4}}=2{{c}^{2}}({{a}^{2}}+{{b}^{2}})\] then the angles opposite to the side C is [J & K 2005]

A. \[45{}^\circ \] or \[135{}^\circ \]
B. \[30{}^\circ \] or \[100{}^\circ \]
C. \[50{}^\circ \] or \[100{}^\circ \]
D. \[60{}^\circ \] or \[120{}^\circ \]
Answer» B. \[30{}^\circ \] or \[100{}^\circ \]
1833.

If in a \[\Delta ABC\], the altitudes from the vertices A, B, C on opposite sides are in H.P. then \[\sin A,\,\sin B,\sin C\] are in    [AIEEE 2005]

A. A.G.P.
B. H.P.
C. G.P.
D. A.P.
Answer» E.
1834.

In \[\Delta ABC,\]\[1-\tan \frac{A}{2}\tan \frac{B}{2}=\] [Roorkee 1973]

A. \[\frac{2c}{a+b+c}\]
B. \[\frac{a}{a+b+c}\]
C. \[\frac{2}{a+b+c}\]
D. \[\frac{4a}{a+b+c}\]
Answer» B. \[\frac{a}{a+b+c}\]
1835.

The area of triangle \[ABC,\] in which \[a=1,\ b=2\], \[\angle C=60{}^\circ \]is      [MP PET 2004]

A. \[\frac{1}{2}\]
B. \[\sqrt{3}\]
C. \[\frac{\sqrt{3}}{2}\]
D. \[\frac{3}{2}\]
Answer» D. \[\frac{3}{2}\]
1836.

In a triangle \[ABC\], if \[b+c=2a\] and \[\angle A=60{}^\circ ,\] then \[\Delta ABC\] is [MP PET 2004]

A. Scalene
B. Equilateral
C. Isosecles
D. Right angled
Answer» C. Isosecles
1837.

In \[\Delta ABC,\]\[{{a}^{2}}+{{b}^{2}}+{{c}^{2}}=ac+ab\sqrt{3},\]then triangle is  [MP PET 2004]

A. Equilateral
B. Isosceles
C. Right angled
D. None of these
Answer» D. None of these
1838.

In a \[\Delta ABC,\,\,{{a}^{2}}\sin \,\,2C+{{c}^{2}}\sin 2A=\] [EAMCET 2001]

A. \[\Delta \]
B. \[2\Delta \]
C. \[3\Delta \]
D. \[4\Delta \]
Answer» E.
1839.

If in a triangle ABC, a, b, c and angle A is given and \[c\sin A

A. \[{{b}_{1}}+{{b}_{2}}=2c\cos A\]
B. \[{{b}_{1}}+{{b}_{2}}=c\cos A\]
C. \[{{b}_{1}}+{{b}_{2}}=3c\cos A\]
D. \[{{b}_{1}}+{{b}_{2}}=4c\sin A\]
Answer» B. \[{{b}_{1}}+{{b}_{2}}=c\cos A\]
1840.

If a triangle \[PQR\], \[\sin P,\ \sin Q,\ \sin R\]are in A.P., then [IIT 1998]

A. The altitudes are in A.P.
B. The altitudes are in H.P.
C. The medians are in G.P.
D.   The medians are in A.P.
Answer» C. The medians are in G.P.
1841.

In a \[\Delta ABC,\]if \[\frac{\sin A}{\sin C}=\frac{\sin (A-B)}{\sin (B-C)},\]then \[{{a}^{2}},\ {{b}^{2}},\ {{c}^{2}}\] are in    [Pb. CET 2001; Karnataka CET 1999]

A. A.P.
B. G.P.
C. H.P.
D. None of these
Answer» B. G.P.
1842.

In a triangle \[PQR\], \[\angle R=\frac{\pi }{2}.\]If \[\tan \left( \frac{P}{2} \right)\]and \[\tan \left( \frac{Q}{2} \right)\]are the roots of the equation \[a{{x}^{2}}+bx+c=0(a\ne 0).\] then [IIT 1999; MP PET 2000; AIEEE 2005]

A. \[a+b=c\]
B. \[b+c=a\]
C. \[a+c=b\]
D. \[b=c\]
Answer» B. \[b+c=a\]
1843.

If the sides of a triangle are \[3,\ 5,\ 7,\]then [MP PET 1996]

A. All its angles are acute
B. One angle is obtuse
C. Triangle is right angled
D. None of these
Answer» C. Triangle is right angled
1844.

If \[y=x\tan \frac{\alpha +\beta }{2}\], then \[\tan A+\tan B+\tan C=\]

A. \[\frac{a+b+c}{abc}\]
B. \[0\]
C. \[\tan A\tan B\tan C\]
D. \[\tan A\tan B+\tan B\tan C+\tan C\tan A\]
Answer» D. \[\tan A\tan B+\tan B\tan C+\tan C\tan A\]
1845.

In\[\Delta ABC,\] if \[\cos A+\cos C=4{{\sin }^{2}}\frac{1}{2}B,\] then \[a,b,c\] are in

A. A. P.
B. G. P.
C. H. P.
D. None of these
Answer» B. G. P.
1846.

If  in a triangle \[ABC\], \[2\cos A=\sin B\,\text{cosec}\,C,\] then [MP PET 1996]

A. \[a=b\]
B. \[b=c\]
C. \[c=a\]
D. \[2a=bc\]
Answer» D. \[2a=bc\]
1847.

In a \[\Delta ABC\], \[a,\ b,\ A\]are given and \[{{c}_{1}},\ {{c}_{2}}\]are two values of the third side c. The sum of the areas of two triangles with sides \[a,\ b,\ {{c}_{1}}\] and \[a,b,\ {{c}_{2}}\] is

A. \[\frac{1}{2}{{b}^{2}}\sin 2A\]
B. \[\frac{1}{2}{{a}^{2}}\sin 2A\]
C. \[{{b}^{2}}\sin 2A\]
D. None of these
Answer» B. \[\frac{1}{2}{{a}^{2}}\sin 2A\]
1848.

In a \[\Delta ABC\] \[a,\ c,A\]are given and \[{{b}_{1}},\ {{b}_{2}}\]are two values of the third side b such that \[{{b}_{2}}=2{{b}_{1}}\]. Then \[\sin A=\]

A. \[\sqrt{\frac{9{{a}^{2}}-{{c}^{2}}}{8{{a}^{2}}}}\]
B. \[\sqrt{\frac{9{{a}^{2}}-{{c}^{2}}}{8{{c}^{2}}}}\]
C. \[\sqrt{\frac{9{{a}^{2}}+{{c}^{2}}}{8{{a}^{2}}}}\]
D. None of these
Answer» C. \[\sqrt{\frac{9{{a}^{2}}+{{c}^{2}}}{8{{a}^{2}}}}\]
1849.

In triangle ABC and DEF, AB = DE, AC = EF and \[\angle A=2\angle E\]. Two triangles will have the same area, if angle A is equal to

A. \[\frac{\pi }{3}\]
B. \[\frac{\pi }{2}\]
C. \[\frac{2\pi }{3}\]
D. \[\frac{5\pi }{6}\]
Answer» D. \[\frac{5\pi }{6}\]
1850.

We are given b, c and \[\sin B\] such that B is acute and \[b

A. No triangle is possible
B. One triangle is possible
C. Two triangles are possible
D. A right angled triangle is possible
Answer» B. One triangle is possible