# Trigonometric equations....

• September 30th 2008, 04:24 PM
Naur
Trigonometric equations....
For lack of a better name...

Anyway, here's my problem. In the answers (second image uploaded), they've stated that it's okay to use values outside the domain, as long as they'll eventually fit in the domain as values of x. Is this okay?
This would be meaningless without the images...so take a look at them :D
• September 30th 2008, 04:51 PM
icemanfan
The given domain is $[0, 2\pi]$. This specifies what values of x are legal, not what values of 2x are legal. So if x can be any value in the interval $[0, 2\pi]$, then 2x can be anywhere in the interval $[0, 4\pi]$.
• September 30th 2008, 05:00 PM
Naur
Ah, that makes sense. Thank you. =]