MCQ 11 Mark
The domain of function $\cos ^{-1}(2 x-3)$ is :
- A$[-1,1]$
- B$(1,2)$
- C(-1,1)
- ✓$[1,2]$
Answer
View full question & answer→Correct option: D.
$[1,2]$
(D)
The domain of $\cos ^{-1}(\theta)$ is $-1 \leq \theta \leq 1$$
\begin{array}{ll}
\text { So, } & -1 \leq 2 x-3 \leq 1 \\
\Rightarrow & -1+3 \leq 2 x-3+3 \leq 1+3 \\
\Rightarrow & 2 \leq 2 x \leq 4 \\
\Rightarrow & 1 \leq x \leq 2 \\
\Rightarrow & x \in[1,2]
\end{array}
$
Hence correct option is (D).
The domain of $\cos ^{-1}(\theta)$ is $-1 \leq \theta \leq 1$$
\begin{array}{ll}
\text { So, } & -1 \leq 2 x-3 \leq 1 \\
\Rightarrow & -1+3 \leq 2 x-3+3 \leq 1+3 \\
\Rightarrow & 2 \leq 2 x \leq 4 \\
\Rightarrow & 1 \leq x \leq 2 \\
\Rightarrow & x \in[1,2]
\end{array}
$
Hence correct option is (D).

