[Math] Could use some assistance...

Hey, I'm trying to solve this problem and would appreciate some help or even the answer.

The solutions to cos Θ <= 0 on the interval 0 <= Θ <= 2π are precisely those values of Θ that satisfy: A: 0 <= Θ <= π/2 B: π/2 <= Θ <= π C: π/2 <= Θ <= 2π D: π <= Θ <= 2π E: 3π/2 <= Θ <= 2π

Thanks a lot,
- Phaaze

Not really sure on the notation, mine seems to be different, but to have a cos value that's negative, you'd have to have an angle somewhere in [π/2, 3π/2]...

i don't understand the notation neither, but yea, cos is negative when your angle is between 90°-270° (+n*360)

The notation isn't too wierd. Just take the given notation and convert it to interval notation by getting rid of the theta and less/more than signs. Anyway, like I said on MSN, the answer that makes sense is B, however, it IS negative for more than just [pi/2, pi], but I can't remember how long one 'revolution' of a cos wave is.

Originally Posted by Andrew R but I can't remember how long one 'revolution' of a cos wave is.