cos (17π/3) =______________
A. 1/2
B. -1/2
C. √3/2
D. -√3/2
This question was addressed to me in an interview for job.
This key question is from Trigonometric Functions in chapter Trigonometric Functions of Mathematics – Class 11
Right answer is A. 1/2
Easiest explanation: cos (17π/3) = cos (2π*3 – π/3)
{cos (2nπ-x)=cos x}
= cos(π/3) = 1/2.