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Find the principal value of the following: cos-1(-1/2) - Mathematics

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Question

Find the principal value of the following:

`cos^(-1) (-1/2)`

Sum
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Solution

 Let `cos^(-1) (-1/2)` = y

⇒ cos y = `-1/2 = -cos pi/3 = cos (pi - pi/3)`

We know that the range of the principal value branch of cos−1 is [0, π] and `cos((2pi)/3) = 1/2`.

Therefore, the principal value of `cos^(-1) (-1/2)` is `(2pi)/3`.

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Chapter 2: Inverse Trigonometric Functions - Exercise 2.1 [Page 41]

APPEARS IN

NCERT Mathematics Part 1 and 2 [English] Class 12
Chapter 2 Inverse Trigonometric Functions
Exercise 2.1 | Q 5 | Page 41

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