Question icon
12 grade maths others

Find the principal value of: cos⁻¹(−1/(√2))

Profile image of Aniket Singh
9 Months agoGrade
Answers icon

1 Answer

Profile image of Askiitians Tutor Team
ApprovedApproved Tutor Answer9 Months ago

The principal value of the inverse cosine function, cos⁻¹(x), is the angle whose cosine is x, typically within the range of 0 to π (0 to 180 degrees).

Finding the Value

To find the principal value of cos⁻¹(−1/(√2)), we need to determine the angle where the cosine equals −1/(√2).

Identifying the Angle

  • The cosine of 135 degrees (or 3π/4 radians) is −1/(√2).
  • This angle lies within the specified range for the principal value.

Final Result

Thus, the principal value of cos⁻¹(−1/(√2)) is 3π/4 radians or 135 degrees.