Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store
seo-qna
SearchIcon
banner

Find the principal value of cos1(32).

Answer
VerifiedVerified
519.6k+ views
like imagedislike image
Hint: The principal value of an inverse trigonometric function at a point x is the value of the inverse function at the point x, which lies in the range of the principal branch. The principal value of the cosine function is from [0,π]. From the table we will find the value of the function within the principal range, to get our final answer.

Complete step-by-step answer:

The values of the cosine function are-

Function0o30o45o60o90o
cos13212120



In the given question we need to find the principal value of cos1(32). We know that for the cosine function to be positive, the angle should be acute, that is less than 90o.
We know that cos30o=32.
cos1(32)=30o
We know that π rad = 180o, so
cos1(32)=π6
This is the required value.

Note: In such types of questions, we need to strictly follow the range of the principal values that have been specified. The principal value of the cosine function in this case ranges from 0o to 90o. This is because there can be infinite values of any inverse trigonometric functions.One common mistake is that students get confused between the sine and the cosine functions, and often write the values of sine function or vice versa.

Latest Vedantu courses for you
Grade 11 Science PCM | CBSE | SCHOOL | English
CBSE (2025-26)
calendar iconAcademic year 2025-26
language iconENGLISH
book iconUnlimited access till final school exam
tick
School Full course for CBSE students
PhysicsPhysics
ChemistryChemistry
MathsMaths
₹41,848 per year
Select and buy