Gradients and Equations

[monkeee]

1. What is the gradient and the equation of the line AB?
2. What is the gradient of CD and equation of CD?
3. What is the point of intersection of AB and CD?
4. What is the length of the lines AB and CD?

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I need working and answers so I can just revise and understand this properly etc​

 

[mmm4444bot]

You need to start showing your work, etc.

What is your meaning, exactly, when you post that you need to "just revise" ?

What are you trying to revise?

 

[Bob Brown MSEE]

Hi monkeee

This is your second posting?
I am new to this site also.


This is a Forum (like a conversation). You show what you are working on, and where we might help.
We get you going again .. its that simple. Then you answer back so that we know that we helped. Often, you will progress and get stuck again. That's ok. Its not uncommon for several passes between us, a conversation.

You have made the first step.
We can only talk about one thing at a time.
So what don't you understand about ...
1. What is the gradient and the equation of the line AB?

Tell me how you would answer it?
I have a question for you: What does gradient mean in your class? Is it slope?

 

[HallsofIvy]

It is easy to get the gradient and equation of AB but impossible to get those for CD without knowing exactly where D is! Does your problem include the condition that D is the midpoint of AB?

 

[monkeee]

Well this is the first lot of questions with a LOT more of the same. So I figure if I can see this worked out, then I'll be able to understand it and work on the others myself. I missed this in class, have no notes and just don't know what to do or how to get correct answers to learn from to do the next set.

 

[JeffM]

Well this is the first lot of questions with a LOT more of the same. So I figure if I can see this worked out, then I'll be able to understand it and work on the others myself. I missed this in class, have no notes and just don't know what to do or how to get correct answers to learn from to do the next set.

The people who are TRYING to help you asked two questions. You did not answer either. How can we help you if you pay no attention?

 

[mmm4444bot]

I missed this in class, have no notes and just don't know what to do.

The lessons that you need to research involve writing equations for lines from given coordinates of points on those lines.

As we have no way of know how long you've been sick or how many class days you've missed, we really have no idea where to begin with you.

You've learned this: (x, y) because I saw your plot.

Do you know that (x₁, y₁) also means some point's coordinates. We see that the point is being called point1. The subscripts are used to distinguish between different points, like point1, point2, and so on.

(x₂, y₂) is how we express (again, symbolically) the coordinates for point2. You'll see formulas that show the coordinates of two different points this way. You are free to choose which of the two points on a line is called point1 -- it doesn't matter -- unless, of course, they specifically assign those names to specific points for you.

Here are some Google results for lesson sites on how to write the equation for a line when you know the coordinates of two points on the line.

Skim through some of those sites; see what makes sense to you. Come back with your specific questions about things you see that don't make sense. Then, we will have a better idea of how much catching up you require.

:idea: Have you contacted your school to inquire about face-to-face tutoring resources or suggestions about making up lost class experience?

 

[monkeee]

For question 1 I would try to find the gradients, multiply them, then...?... How do I get the gradients, like what do I need to do with what numbers?

 

[Bob Brown MSEE]

1. What is the gradient and the equation of the line AB?

What are the coordinents of the end points of AB?
Would you be able to plot them?
How do you define gradient? Is it the same thing as slope?

 

[JeffM]

For question 1 I would try to find the gradients, multiply them, then...?... How do I get the gradients, like what do I need to do with what numbers?

Wow, you pay no attention at all. I am going to assume (because you have not told us despite being asked) that "gradient" means "slope." I am also going to assume that you did not look at the google reference supplied by mmm.

Do you know the general form of a linear equation? If so, what is it? If you do not know, click on the URL of the site below: http://www.purplemath.com/modules/strtlneq.htm

What does that suggest to you about how to solve part 1 of your problem?

What does the site tell you is the generally most useful form for a linear equation?

How does the site tell you to use the x and y values of two given points to make that general form of linear equation specifically apply to the given points? So what equation does that result in for your problem?

Now for the part 2 of your problem. As HallsOfIvy asked you earlier, what does your problem say about point C and line CD with reference to line AB? We can't see your problem. You have to tell us what it says.

 

[Deleted member 4993]

Well this is the first lot of questions with a LOT more of the same. So I figure if I can see this worked out, then I'll be able to understand it and work on the others myself. I missed this in class, have no notes and just don't know what to do or how to get correct answers to learn from to do the next set.

Did you look at the worked out example problems in your text-book?

 

[mmm4444bot]

For question 1 I would try to find the gradients, multiply them, then...?

How do I get the gradients, like what do I need to do with what numbers?

Gradient is another word for slope. Yes, you need to find the gradient. This is a number, and it gives a measurement of how "slanted" a line is.

Each line has only one gradient. No, you do not multiply the gradients of different lines (although, sometimes it's handy to know that the product of perpendicular gradients is always -1).

There is a formula for slope (gradient). You need to use this formula, to determine the slope of the line passing through points A and B.

The slope formula uses the coordinates of two points. You have the coordinates of two points (A and B). Pick one of them, and call it point1; the other point is point2.

The symbol m is often used to represent the slope. Here is the formula:

m = (y₂ - y₁)/(x₂ - x₁)

See how easy? This is exactly as explained in the videos and so many of those lessons above.

Slope is simply the difference of the two points' y-coordinates DIVIDED BY the difference of the two points' x-coordinates.

Or, said another way, when going from one point to the other: slope equals the change in y (called RISE) divided by the change in x (called RUN).

Substitute the given coordinates into the slope formula, and do the arithmetic.

Please show us what you get for the slope of line AB.

If none of this makes any sense to you, then it probably won't serve you well for us to continue leading you by the hand through this exercise. If you are unable to understand the lessons we provided (or your own text book), then you need classroom help -- that is, you need to speak with your instructor, as we're not set up to teach days of course material on these boards. Cheers.

 

[Mrspi]

Gradient is another word for slope. Yes, you need to find the gradient. This is a number, and it gives a measurement of how "slanted" a line is.

Each line has only one gradient. No, you do not multiply the gradients of different lines (although, sometimes it's handy to know that the product of perpendicular gradients is always -1).

There is a formula for slope (gradient). You need to use this formula, to determine the slope of the line passing through points A and B.

The slope formula uses the coordinates of two points. You have the coordinates of two points (A and B). Pick one of them, and call it point1; the other point is point2.

The symbol m is often used to represent the slope. Here is the formula:

m = (x₂ - x₁)/(y₂ - y₁)

See how easy? This is exactly as explained in the videos above.

Slope is simply the difference of the two points' x-coordinates DIVIDED BY the difference of the two points' y-coordinates.

Or, said another way, when going from one point to the other: slope equals the change in x (called RUN) divided by the change in y (called RISE).

Substitute the given coordinates into the slope formula, and do the arithmetic.

Please show us what you get for the slope of line AB.

If none of this makes any sense to you, then it probably won't serve you well for us to continue leading you by the hand through this exercise. If you are unable to understand the lessons we provided (or your own text book), then you need classroom help -- that is, you need to speak with your instructor, as we're not set up to teach days of course material on these boards. Cheers.

Actually, that formula for slope should have (y₂ - y₁) / (x₂ - x₁), because the slope or gradient is usually stated as "rise / run" or "vertical change/horizontal change".

 

[mmm4444bot]

I'm glad that you caught it quickly, Mrs. Pi !

ooog -- my brain is not functioning so good today; I seem to be confused with a number of posts. I'll fix that really weird mistake, and send a pm notice, too, although I'm thinking that monkeee is not really seeing much of anything that I post.

Crawling back into the sub-basement, now...