Q.

The domain of the function defined by f(x)=sin-1(x−1) is:

1 [1, 2]  
2 [−1, 1]  
3 [0, 1]  
4 None of these  

Ans.

(1)

Ans:         [1, 2]

Explanation:

We know that sin-1x is defined for

                   x∈[-1,1]

∴  f(x)=sin-1x-1 is defined if

⇒                 0≤x-1≤1

                        [∵ x-1≥0 and -1≤x-1≤1]

⇒ 0≤x-1≤1

⇒ 1≤x≤2

∴  x∈[1,2]