Math Is Fun Forum

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Describe Set of All Points

A. Plot the points (0, 3), (1, 3), (-2, 3), and (-4, 3).

B. Describe the set of all points of the form (x, 3), where x is a real number.

NOTE:

I know how to plot points on the xy-plane.
My question concerns part B.

Any hints?

amnkb

Member

Registered: 2023-09-19

Posts: 253

Re: Describe Set of All Points

A. Plot the points (0, 3), (1, 3), (-2, 3), and (-4, 3).

B. Describe the set of all points of the form (x, 3), where x is a real number.

how does your book do similar examples?
like are you supposed o do set notation or maybe a line equation?

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Describe Set of All Points

A. Plot the points (0, 3), (1, 3), (-2, 3), and (-4, 3).

B. Describe the set of all points of the form (x, 3), where x is a real number.

how does your book do similar examples?
like are you supposed o do set notation or maybe a line equation?

The textbook does not give examples for every problem.
Do you have a hint for me or not?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,196

Re: Describe Set of All Points

If you have the plot ready, you should notice these points are all in a straight line. generally y = mx + c will give you the equation. When the line is parallel with one of the axes, the equation is even simpler: either y = constant or x = constant. I'll leave you to decide which and what the constant is.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

amnkb

Member

Registered: 2023-09-19

Posts: 253

Re: Describe Set of All Points

A. Plot the points (0, 3), (1, 3), (-2, 3), and (-4, 3).

B. Describe the set of all points of the form (x, 3), where x is a real number.

how does your book do similar examples?
like are you supposed o do set notation or maybe a line equation?

The textbook does not give examples for every problem.
Do you have a hint for me or not?

my hint was to check the book to see if they showed what sort of sol'n they want
like i said, theres more than one way to answer this
they say 'set' so i guess use set not'n
{(x,y) in RxR | x in R, y = 3}

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Describe Set of All Points

A. Plot the points (0, 3), (1, 3), (-2, 3), and (-4, 3).

B. Describe the set of all points of the form (x, 3), where x is a real number.

how does your book do similar examples?
like are you supposed o do set notation or maybe a line equation?

The textbook does not give examples for every problem.
Do you have a hint for me or not?

my hint was to check the book to see if they showed what sort of sol'n they want
like i said, theres more than one way to answer this
they say 'set' so i guess use set not'n
{(x,y) in RxR | x in R, y = 3}

The textbook does not give a sample problem for this question.

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Describe Set of All Points

If you have the plot ready, you should notice these points are all in a straight line. generally y = mx + c will give you the equation. When the line is parallel with one of the axes, the equation is even simpler: either y = constant or x = constant. I'll leave you to decide which and what the constant is.

Bob

Ok. I will work on this problem later when back at the house.

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Describe Set of All Points

If you have the plot ready, you should notice these points are all in a straight line. generally y = mx + c will give you the equation. When the line is parallel with one of the axes, the equation is even simpler: either y = constant or x = constant. I'll leave you to decide which and what the constant is.

Bob

I noticed that the value of y is constant for each given point.
So, y = 3 is the line which is parallel to the x-axis.

Now, the points given are as follows:

(0, 3), (1, 3), (-2, 3), and (-4, 3)

The values of x = { 0, 1, -2, -4 }.

You say?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,196

Re: Describe Set of All Points

all points of the form (x, 3)

So write in set notation like this:

ie. Not just the originally given points but all in the line.

B

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Describe Set of All Points

all points of the form (x, 3)

So write in set notation like this:

ie. Not just the originally given points but all in the line.

B

Bob,

I am not too familiar with set notation language.
Can you please interpret what this means in English?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,196

Re: Describe Set of All Points

You can 'read' this as if maths is a language.

Curly brackets means the set

with the points of the form (x,3)

: such that

x is a member of the real numbers.

Put the underlined bits together and you get

the set with the points of the form (x,3) such that x is a member of the real numbers.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Describe Set of All Points

You can 'read' this as if maths is a language.

Curly brackets means the set

with the points of the form (x,3)

: such that

x is a member of the real numbers.

Put the underlined bits together and you get

the set with the points of the form (x,3) such that x is a member of the real numbers.

Bob

This was helpful. I thank you for the translation.