Advertisements
Advertisements
Question
The principal value of `cos^-1 (- 1/2)` is ______.
Fill in the Blanks
Advertisements
Solution
The principal value of `cos^-1 (- 1/2)` is `(2pi)/3`.
Explanation:
Let `cos^1 (- 1/2)` = x
⇒ cos x = `-1/2`
⇒ cos x = `cos(- pi/3)`
⇒ cos x = `cos(pi - pi/3)`
= `cos (2pi)/3`
∴ x = `(2pi)/3 ∈ [0, pi]`
shaalaa.com
Is there an error in this question or solution?
