A function which does not have a break in its graph is called a continuous function. A function f(x) is said to be continuous at a point x=a, if f(a) exists and the value of f(a) is finite, left hand limit is equal to the right hand limit and both are finite and f(x) = f(a)
Question 1: Let S ={ f: RR | > 0 such that ∀δ> 0, |x-y|< δ, |f(x)- f(y)|< } then
Answer: (d)
Explanation: Check the option (a) and (b) they are incorrect as the function is not continuous.
Question 2: Let f:(0, ) R be uniformly continuous then
(a) f(x) and
f(x) exist
(b) f(x) need not exist but
f(x) exists
(c) f(x) exists and
f(x) need not exist
(d) None exists
Answer: (c)
Explanation: A function is uniformly continuous if for every > 0 there exist.
Question 3: Which of the function is uniform and continuous on interval (0,1)
Answer: (a)
Explanation: f(x) is continuous in (a,b) and if limits exist at endpoints then f(x) is uniformly continuous.
Question 4: f: RR is such that f(0) = 0 and |f’(x)|
5 for all x, we can conclude that f(1) is in
(a) (5,6)
(b) [-5,5]
(c) [1,5]
(d) [-4,4]
Answer: (b)
Explanation: |f’(x)| 5 => -5
f’(x)
5
f’(x) - 5 0
f’(x) – 5 = a
Question 5: Which of the following is uniform continuous on (0,1).
Answer: (a)
Explanation:
Question 6: Let f: RR be a continuous and one-one function then which of the following is true
(a) f is onto
(b) f is either strictly increasing or strictly decreasing
(c) there exists x R
(d) f is unbounded
Answer: (b)
Explanation: f: RR is continuous and one-one.
Question 7:
Answer: (a)
Explanation: It is a sequence of continuous function at x= 0
Question 8: f(x) = log (x)
(a) f(x) is discontinuous on R
(b) f(x) is continuous on R
(c) f(x) is continuous on (0, ∞)
(d) f(x) is defined on R
Answer: (c)
Explanation: log(x) is continuous on (0, ∞), has domain R
Question 9: Which of the following statements is incorrect.
(a)|x| is continuous
(b) tan x cot x and sec x are continuous in their respective domains
(c) Addition and subtraction of a discontinuous function with continuous function may be continuous or discontinuous.
(d) Product and ratio of two continuous function is always continuous provided the denominator is non-zero at a point where we are checking the continuity.
Answer: (c)
Explanation: Addition and subtraction of a discontinuous function.
Question 10: f(x) = |6-x +|x|| is
(a) Discontinuous on R
(b) Continuous on R
(c) Discontinuous at x = 1
(d) has a removable type of discontinuity
Answer: (b)
Explanation: Both functions are continuous hence composition of both functions is also continuous.