Help with Graphing Equations in the Co-ordinate Plane

[939]

1. Relevant equations
1) Let X = [0,4] ⊂ R and y = f (x) = 2 - x/2. Describe the set { x : f (x) < 1, x ∈
X} and graph the set { (x,y) : y = f (x) < 1, x ∈ X} in the co-ordinate plane.

2) Let X = R2+ \{(0,0)} and y = f (x) = x2 /x1. Graph the set { x : f (x) = 1, x ∈ X}
in the co-ordinate plane.

2. The attempt at a solution

1) I am not sure what "Let X = [0,4] ⊂ R" means. As for the graph, is it not merely a line like this "\" stopping just before y = 1?

2) Is it not merely a horizontal line at y = 1?

 

[Ray Vickson]

1. Relevant equations
1) Let X = [0,4] ⊂ R and y = f (x) = 2 - x/2. Describe the set { x : f (x) < 1, x ∈
X} and graph the set { (x,y) : y = f (x) < 1, x ∈ X} in the co-ordinate plane.

2) Let X = R2+ \{(0,0)} and y = f (x) = x2 /x1. Graph the set { x : f (x) = 1, x ∈ X}
in the co-ordinate plane.

2. The attempt at a solution

1) I am not sure what "Let X = [0,4] ⊂ R" means. As for the graph, is it not merely a line like this "\" stopping just before y = 1?

2) Is it not merely a horizontal line at y = 1?

Do you know what the notation [0,4] means? And the answer is YES to your other questions.

RGV

 

[939]

Do you know what the notation [0,4] means? And the answer is YES to your other questions.

RGV

Yes, I'm know 100% what that notation means... If it means something different than what's in the equation, please tell me, if not, thanks a lot for the help, I really appreciate it.

 

[HallsofIvy]

Yes, I'm know 100% what that notation means...

How can you be 100% sure of what [0, 4] means and not know what "Let X = [0,4] ⊂ R" means? And how can you say you know 100% what it means and the ask if it means something different? What do YOU think it means. We can't tell you if it means something different until you tell us that!

 

[939]

How can you be 100% sure of what [0, 4] means and not know what "Let X = [0,4] ⊂ R" means? And how can you say you know 100% what it means and the ask if it means something different? What do YOU think it means. We can't tell you if it means something different until you tell us that!

Sorry, I was sure [0,4] ment x must be equal to or between 0 and 4, and Let X = [0,4] ⊂ R means x be equal to or between 0 and 4 and must be a real number?