My teacher insists that you can find the reference angle for a radian measure by simply removing the number in front of pi (ex. 5pi/4 ref.=pi/4) but it doesnt seem to work with 7pi/5, 3pi/5 and some others i have tried. Is this not true at all?

Question

directrix · Answer

I've not heard of it before but ...

dumbcow · Answer

depends on which quadrant you are in:

Q1: reference angle = angle
Q2: reference angle = pi - angle
Q3: reference angle = angle - pi
Q4: reference angle = 2pi - angle

dumbcow · Answer

as far as that rule your teacher uses...sometimes it works sometimes it doesn't

anonymous · Answer

which quadrants would it work in or would it just work sometimes in every quadrant?

dumbcow · Answer

lets see, it works sometimes in every quadrant 

Q2: if in the form (n-1)pi/n

Q3: if in the form n pi/(n-1)

Q4: if in the form (2n-1)pi/n

anonymous · Answer

and Q1 would just be if the angle had a measure with nothing in front of pi?

anonymous · Answer

sorry that was kind of a dumb question