4 cos(x) + 2 0 [0,2pi] What is the interval notation set?
What I got:
4cos(x) + 2 0
4cos(x) -2
cos(x)-(1/2)
Thus,
x (3pi/4) and (4pi/3)
so....
how would I write this in notation set?

Question

4 cos(x) + 2 > 0 [0,2pi] What is the interval notation set?
What I got:
4cos(x) + 2 > 0
4cos(x) > -2
cos(x)>-(1/2)
Thus,
x > (3pi/4) and (4pi/3)
so....
how would I write this in notation set?

anonymous · Answer

|dw:1347775081147:dw| <---what i got from my calculator

anonymous · Answer

is it:
[0, 3pi/4) u (4pi/3, 2pi]
or:
(3pi/4, 4pi/3)?

anonymous · Answer

The first one!

anonymous · Answer

The curve go up!

anonymous · Answer

aw. no... it says its not correct.

anonymous · Answer

fransisco you should compare with y=-2

anonymous · Answer

Thanks for taking the time @Chlorophyll

anonymous · Answer

I wonder why I'm wrong ?

anonymous · Answer

no. i dont think your wrong . wolframalpha says your right too. im going to complain to the teacher about this.

anonymous · Answer

Thanks for your confirmation,  Fran :)