Page 36 - Mathematics Class - XI

Viva-Voce

1. What is the period of sine curve?
Ans. The period of sine curve is the length of one cycle of the curve. The natural period of the sine curve is 2p.
2. In the graph of y = 2 sin x, 0 ≤ x ≤ p the values of y lies between 1 and –1. Is this statement True or False?
Ans. False.

3. Is the graph of y = sin x continuous?
Ans. Yes, the graph of y = sin x is continuous and extends on either side in symmetrical wave form.
4. What is the difference between 2 sin x and sin 2x?
Ans. 2 sin x is twice the trigonometric function sin x whereas 2x in sin 2x represents angle.

5. What does 6 represent in y = sin 6x?
Ans. In an interval of length 2p, there are 6 periods.
6. What is meant by a periodic function?
Ans. A periodic function is a function that repeats its values in regular intervals or periods.

MCQs

1. The value of sin 7 is
2

a) 4 − 6 − 2 b) 4 6 2 c) 4 6 2 d) None of these
22 2 22

2. If sin x = 1 then find the true statement given below
2
p
a) sin x = sin b) sin x = sin p c) sin x = sin d) None of these
2 4 5

3. Which of the following statement is true?
a) sin A + cos A = 1 b) tan q + cot q = 0 c) both a) and b) d) None of these
2
2
2
2
q
4. If sin q = and q is located in III quadrant then cos is equal to
5 2
1 1
a) b) c) d)
5 10 5 10
5. If A is located in II quadrant and 3 tan A + 4 = 0, then the value of (2 cotA – 5 cosA + sinA) is equal to

a) − 53 b) 23 c) 37 d) 7
10 10 10 10

Answers: 1. a) 4 − 6 − 2 2. b) sin x = sin p 3. a) sin A + cos A = 1
2
2
22 4
23
4. c) 5. b)
5 10
34