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The domain of the function cos1(2x3)\cos^{-1}(2x - 3) is

Solution

Correct Option: 1

The inverse cosine function cos1\cos^{-1} only accepts inputs between 1-1 and 11 (inclusive).


For cos1(2x3)\cos^{-1}(2x - 3) to be defined, the input must satisfy:

12x31-1 \leq 2x - 3 \leq 1


From the left inequality:

12x3-1 \leq 2x - 3

1+32x-1 + 3 \leq 2x

22x2 \leq 2x

1x1 \leq x


From the right inequality:

2x312x - 3 \leq 1

2x1+32x \leq 1 + 3

2x42x \leq 4

x2x \leq 2


Combining both results:

1x21 \leq x \leq 2

Therefore, the domain is [1,2][1, 2].

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