NCERT Exemplar Solutions
Class 11 - Mathematics - Chapter 3: TRIGONOMETRIC FUNCTIONS
Objective Type Questions

Choose the correct answer from the given four options:

Question.  30

If \(\sin\theta + \csc\theta = 2\), then \(\sin^2\theta + \csc^2\theta\) is equal to

(a)

1

(b)

4

(c)

2

(d)

None of these

Question.  31

If \(f(x)=\cos^2 x + \sec^2 x\), then

(a)

\(f(x) < 1\)

(b)

\(f(x)=1\)

(c)

\(2 < f(x) < 1\)

(d)

\(f(x) \ge 2\)

Question.  32

If \(\tan\theta=\dfrac{1}{2}\) and \(\tan\phi=\dfrac{1}{3}\), then the value of \(\theta+\phi\) is

(a)

\(\dfrac{\pi}{6}\)

(b)

\(\pi\)

(c)

0

(d)

\(\dfrac{\pi}{4}\)

Question.  33

Which of the following is not correct?

(a)

\(\sin\theta = -\dfrac{1}{5}\)

(b)

\(\cos\theta = 1\)

(c)

\(\sec\theta = \dfrac{1}{2}\)

(d)

\(\tan\theta = 20\)

Question.  34

The value of \(\tan1^\circ\tan2^\circ\tan3^\circ\dots\tan89^\circ\) is

(a)

0

(b)

1

(c)

\(\dfrac{1}{2}\)

(d)

Not defined

Question.  35

The value of \(\dfrac{1-\tan^2 15^\circ}{1+\tan^2 15^\circ}\) is

(a)

1

(b)

\(\sqrt{3}\)

(c)

\(\dfrac{\sqrt{3}}{2}\)

(d)

2

Question.  36

The value of \(\cos1^\circ\cos2^\circ\cos3^\circ\dots\cos179^\circ\) is

(a)

\(\dfrac{1}{\sqrt{2}}\)

(b)

0

(c)

1

(d)

-1

Question.  37

If \(\tan\theta=3\) and \(\theta\) lies in the third quadrant, then the value of \(\sin\theta\) is

(a)

\(\dfrac{1}{\sqrt{10}}\)

(b)

\(-\dfrac{1}{\sqrt{10}}\)

(c)

\(-\dfrac{3}{\sqrt{10}}\)

(d)

\(\dfrac{3}{\sqrt{10}}\)

Question.  38

The value of \(\tan75^\circ - \cot75^\circ\) is equal to

(a)

\(2\sqrt{3}\)

(b)

2 + \(\sqrt{3}\)

(c)

2 - \(\sqrt{3}\)

(d)

1

Question.  39

Which of the following is correct?

(a)

\(\sin1^\circ > \sin1\)

(b)

\(\sin1^\circ < \sin1\)

(c)

\(\sin1^\circ = \sin1\)

(d)

\(\sin1^\circ = \dfrac{\pi}{18}\sin1\)

Question.  40

If \(\tan\alpha=\dfrac{m}{m+1}\), \(\tan\beta=\dfrac{1}{2m+1}\), then \(\alpha+\beta\) is equal to

(a)

\(\dfrac{\pi}{2}\)

(b)

\(\dfrac{\pi}{3}\)

(c)

\(\dfrac{\pi}{6}\)

(d)

\(\dfrac{\pi}{4}\)

Question.  41

The minimum value of \(3\cos x + 4\sin x + 8\) is

(a)

5

(b)

9

(c)

7

(d)

3

Question.  42

The value of \(\tan3A - \tan2A - \tan A\) is equal to

(a)

\(\tan3A\tan2A\tan A\)

(b)

\(-\tan3A\tan2A\tan A\)

(c)

\(\tan A\tan2A - \tan2A\tan3A - \tan3A\tan A\)

(d)

None of these

Question.  43

The value of \(\sin(45^\circ + \theta) - \cos(45^\circ - \theta)\) is

(a)

\(2\cos\theta\)

(b)

\(2\sin\theta\)

(c)

1

(d)

0

Question.  44

The value of \(\cot\left(\dfrac{\pi}{4}+\theta\right)\cot\left(\dfrac{\pi}{4}-\theta\right)\) is

(a)

-1

(b)

0

(c)

1

(d)

Not defined

Question.  45

\(\cos2\theta\cos2\phi + \sin^2(\theta-\phi) - \sin^2(\theta+\phi)\) is equal to

(a)

\(\sin2(\theta+\phi)\)

(b)

\(\cos2(\theta+\phi)\)

(c)

\(\sin2(\theta-\phi)\)

(d)

\(\cos2(\theta-\phi)\)

Question.  46

The value of \(\cos12^\circ + \cos84^\circ + \cos156^\circ + \cos132^\circ\) is

(a)

\(\dfrac{1}{2}\)

(b)

1

(c)

\(-\dfrac{1}{2}\)

(d)

\(\dfrac{1}{8}\)

Question.  47

If \(\tan A=\dfrac{1}{2}\), \(\tan B=\dfrac{1}{3}\), then \(\tan(2A+B)\) is equal to

(a)

1

(b)

2

(c)

3

(d)

4

Question.  48

The value of \(\sin\dfrac{\pi}{10} - \sin\dfrac{13\pi}{10}\) is

(a)

\(\dfrac{1}{2}\)

(b)

\(-\dfrac{1}{2}\)

(c)

\(-\dfrac{1}{4}\)

(d)

1

Question.  49

The value of \(\sin50^\circ - \sin70^\circ + \sin10^\circ\) is equal to

(a)

1

(b)

0

(c)

\(\dfrac{1}{2}\)

(d)

2

Question.  50

If \(\sin\theta + \cos\theta = 1\), then the value of \(\sin2\theta\) is equal to

(a)

1

(b)

\(\dfrac{1}{2}\)

(c)

0

(d)

-1

Question.  51

If \(\alpha + \beta = \dfrac{\pi}{4}\), then the value of \((1+\tan\alpha)(1+\tan\beta)\) is

(a)

1

(b)

2

(c)

-2

(d)

Not defined

Question.  52

If \(\sin\theta = -\dfrac{4}{5}\) and \(\theta\) lies in the third quadrant, then the value of \(\cos\dfrac{\theta}{2}\) is

(a)

\(\dfrac{1}{5}\)

(b)

-\(\dfrac{1}{\sqrt{10}}\)

(c)

-\(\dfrac{1}{\sqrt{5}}\)

(d)

\(\dfrac{1}{\sqrt{10}}\)

Question.  53

Number of solutions of the equation \(\tan x + \sec x = 2\cos x\) lying in the interval \([0,2\pi]\) is

(a)

0

(b)

1

(c)

2

(d)

3

Question.  54

The value of \(\sin\dfrac{\pi}{18} + \sin\dfrac{\pi}{9} + \sin\dfrac{2\pi}{9} + \sin\dfrac{5\pi}{18}\) is given by

(a)

\(\sin\dfrac{7\pi}{18} + \sin\dfrac{4\pi}{9}\)

(b)

1

(c)

\(\cos\dfrac{\pi}{6} + \cos\dfrac{3\pi}{7}\)

(d)

\(\cos\dfrac{\pi}{9} + \sin\dfrac{\pi}{9}\)

Question.  55

If \(A\) lies in the second quadrant and \(3\tan A + 4 = 0\), then the value of \(2\cot A - 5\cos A + \sin A\) is equal to

(a)

-\(\dfrac{53}{10}\)

(b)

\(\dfrac{23}{10}\)

(c)

\(\dfrac{37}{10}\)

(d)

\(\dfrac{7}{10}\)

Question.  56

The value of \(\cos^2 48^\circ - \sin^2 12^\circ\) is

(a)

\(\dfrac{\sqrt{5}+1}{8}\)

(b)

\(\dfrac{\sqrt{5}-1}{8}\)

(c)

\(\dfrac{\sqrt{5}+1}{5}\)

(d)

\(\dfrac{\sqrt{5}+1}{2\sqrt{2}}\)

Question.  57

If \(\tan\alpha=\dfrac{1}{7}\), \(\tan\beta=\dfrac{1}{3}\), then \(\cos2\alpha\) is equal to

(a)

\(\sin2\beta\)

(b)

\(\sin4\beta\)

(c)

\(\sin3\beta\)

(d)

\(\cos2\beta\)

Question.  58

If \(\tan\theta=\dfrac{a}{b}\), then \(b\cos2\theta + a\sin2\theta\) is equal to

(a)

a

(b)

b

(c)

\(\dfrac{a}{b}\)

(d)

None

Question.  59

If for real values of \(x\), \(\cos\theta = x + \dfrac{1}{x}\), then

(a)

\(\theta\) is an acute angle

(b)

\(\theta\) is right angle

(c)

\(\theta\) is an obtuse angle

(d)

No value of \(\theta\) is possible

NCERT Exemplar Solutions Class 11 – Mathematics – Chapter 3: TRIGONOMETRIC FUNCTIONS – Objective Type Questions | Detailed Answers