NCERT Class 12 · Ch 2 Exercise 2.1 · Q9
NCERT Class 12 Maths · Chapter 2 Inverse Trigonometric Functions · Exercise 2.1 Question 9
Find the principal value of cos⁻¹(−1/√2).
💡 Concept Hints
- Recall the principal range of the inverse function before simplifying.
- Find an angle with the required trigonometric value, then verify it belongs to the principal range.
✅ Step-by-Step Solution
Final Answer: 3π/4
- The principal range is [0,π].
- cos(3π/4)=−1/√2.
- The angle 3π/4 belongs to that range, so it is the required value.
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