SOLUTION: Hi, please help me solve this problem: Is this true of false: If alpha and beta are in standard position and cos alpha equals cos beta, then alpha and beta must be coterminal.

Algebra ->  Trigonometry-basics -> SOLUTION: Hi, please help me solve this problem: Is this true of false: If alpha and beta are in standard position and cos alpha equals cos beta, then alpha and beta must be coterminal.       Log On


   



Question 395392: Hi, please help me solve this problem:
Is this true of false: If alpha and beta are in standard position and cos alpha equals cos beta, then alpha and beta must be coterminal.

Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
Not necessarily true. On the unit circle, the cosine is represented by the x-coordinate. For example, pi%2F4, and 7pi%2F4 have the same x-coordinate, and thus the same cosine value. However they are not co-terminal.