Union and Intersection - CONFUSING! (1 Viewer)

[lookoutastroboy]

Hey guys (hope you can read most, if not all of it)

A thign currently that I am having trouble with would definitely be the union and intersection (graphing inequalities on the number plane). I mean I just want to know how comeon some graphs where there is a union for example, (just say there are two lines, one marked x + 2y >_ 6 and the other marked y< 3x - 1 with a union). Drawing this on a graph why the hell would the line x + 2y = 6 have some part broken and a part unbroken. Why the hell would the line y = 3x - 1 be all unbroken and not one part broken? Just like the union (the intersection), why is one part of a line broken and the other unbroken, vice versa, how do you know when to make it this way? Lastly, I got this question (sorry I couldnt post it here - hope you can imagine this)with like a combined region of two lines (either an intersection or a union), one line marked y= 1 with the region above it all coloured and a line marked x = -1 with it coloured all on the right of it. The only white space between the two lines is the area on the left hand corner from which the lines intersect each other. Both lines have one part unbroken, the other broken. It says to say if it is an intersection or a union (description of it) and the answer says y > 1 U x > -1. How would you be able to identify this????




Thanks for reading all of this if you got this far.
Thanks again in advance, Lookoutastroboy

 

[ratcher0071]

Hey guys (hope you can read most, if not all of it)

A thign currently that I am having trouble with would definitely be the union and intersection (graphing inequalities on the number plane). I mean I just want to know how comeon some graphs where there is a union for example, (just say there are two lines, one marked x + 2y >_ 6 and the other marked y< 3x - 1 with a union). Drawing this on a graph why the hell would the line x + 2y = 6 have some part broken and a part unbroken. Why the hell would the line y = 3x - 1 be all unbroken and not one part broken? Just like the union (the intersection), why is one part of a line broken and the other unbroken, vice versa, how do you know when to make it this way? Lastly, I got this question (sorry I couldnt post it here - hope you can imagine this)with like a combined region of two lines (either an intersection or a union), one line marked y= 1 with the region above it all coloured and a line marked x = -1 with it coloured all on the right of it. The only white space between the two lines is the area on the left hand corner from which the lines intersect each other. Both lines have one part unbroken, the other broken. It says to say if it is an intersection or a union (description of it) and the answer says y > 1 U x > -1. How would you be able to identify this????




Thanks for reading all of this if you got this far.
Thanks again in advance, Lookoutastroboy

You just confused me

Intersection - AND - upside down U
Union - OR - U

<=, >= would make the line not broken (so full solid line)
<, > would make the line broken (or dashed)

 

[TBK11]

too late to be doin equations im gone