Find the domain and range of the following functions.
(i) f (x) = cos − 1
, where [ . ] denotes the greatest integer function .
(ii) f (x) =
where [ . ] denotes the greatest integer function
(iii) f (x) = sin − 1
, where [ . ] denotes greatest integer function .
(iv) f (x) = log [x − 1] sin x , where [ ] denotes greatest integer function .
(v) f(x) = tan –1
+
+
, (where [ ] denotes greatest integer function)
Text Solution
Verified by Experts(I) [X]; (I) [X]
(i) For domain (i) [x] > 0 and [x] ≠ 1 so [x] ≥ 2, so x ∈ [2, ∞ )
for range if x ∈ [2, ∞ ), then
= 1 so f(x) = cos –1 0 = 
Range of f(x) = 
(ii) f(x) = 
D : 0 < log 2 [x 2 + 4x + 5] ≤ 1
or 1 < [x 2 + 4x + 5] ≤ 2 ⇒ [x 2 + 4x + 5] = 2
or 2 ≤ x 2 + 4x + 5 < 3
D : x ∈ (–2 –
, – 3]
[–1, –2 +
)
R : {0}
(iii) f(x) = sin –1
⇒ –1 ≤ log 2
< 2 ⇒
≤
< 4
⇒ x ∈ (–
, –1] ∪ [1,
) and R : 
(iv) f(x) = log [x – 1] sinx
sin x > 0 ⇒ x ∈ (2n π ,(2n+1) π )
here [x – 1] > 0 & [x – 1]
1 ⇒ x ∈ [3,
)
Domain x ∈ [3, π )
.
For range sin x ∈ (0, 1] and [x – 1] ∈ [2, ∞ ) so range ∈ (– ∞ , 0]
(v) f(x) = tan –1
+ 
Domain : (i) [x] + [–x] ≥ 0 ⇒ x ∈ Ι
(ii) 2 – | x | ≥ 0 ⇒ |x| ≤ 2 ⇒ x ∈ [–2, 2]
(iii) x ≠ 0
For domain (i) ∩ (ii) ∩ (iii)
Domain : {–2, –1, 1, 2}
Range : 

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