Thread: Heeelp linear algebraaa PLS :D

1. Heeelp linear algebraaa PLS :D

http://imgur.com/a/stANL

Q2 C) I am not sure what it means w-u,u,v or how to approach.

Also Q3) b,c,d I dont think my lecturer covered in any great depth and actually have no idea how to do O_o lecturer jumps so much shit.

For 3) a) I got r=(1,1,1) + s(1,0,1) + t(0,2,2), but dont know how to convert to cartesian to find if points lie on it. EDIT: Got x+2y-z=2, but now c) idk

Oh also, does not contain 0,0,0 and 0,0,2 right?

2. Re: Heeelp linear algebraaa PLS :D

Do it yourself, mate.

You're too worried about how to do these questions and whether it's something that you need to learn rather than exercising your problem solving skills.

Here I demonstrate Q3 (a), which you CAN do.

What is the structure of a cartesian equation in R3? ax+by+cz=d, where a, b, c, d are known constants. So, you need (x, y, z).

Where do you get (x, y, z) from what you have?

r = (x, y, z) = (1,1,1) + s(1,0,1) + t(0,2,2)

So, x = __, y = __, z = __.

You're nearly done but the problem here is you figure it out? Which is easily solved with your knowledge.

3. Re: Heeelp linear algebraaa PLS :D

Originally Posted by He-Mann
Do it yourself, mate.

You're too worried about how to do these questions and whether it's something that you need to learn rather than exercising your problem solving skills.

Here I demonstrate Q3 (a), which you CAN do.

What is the structure of a cartesian equation in R3? ax+by+cz=d, where a, b, c, d are known constants. So, you need (x, y, z).

Where do you get (x, y, z) from what you have?

r = (x, y, z) = (1,1,1) + s(1,0,1) + t(0,2,2)

So, x = __, y = __, z = __.

You're nearly done but the problem here is you figure it out? Which is easily solved with your knowledge.
I got a) I just wasn't sure about b) but got that eventually now just c) and d)

also, cant see your latez for some reason

4. Re: Heeelp linear algebraaa PLS :D

OK is c)

x-1=(y-1)/2=z-2 the equation of the line?

5. Re: Heeelp linear algebraaa PLS :D

There's no LaTeX present.

Hint for (c) is "what condition is required for 2 vectors to be orthogonal?" and (d) Euclid

6. Re: Heeelp linear algebraaa PLS :D

Originally Posted by He-Mann
There's no LaTeX present.

Hint for (c) is "what condition is required for 2 vectors to be orthogonal?" and (d) Euclid
How are the answers ive given so far, above?

7. Re: Heeelp linear algebraaa PLS :D

Originally Posted by hayabusaboston
How are the answers ive given so far, above?
I haven't done any computations but could you explain how you got r=(1,1,1) + s(1,0,1) + t(0,2,2) because this disagrees with my understanding of planes. Sorry for the backtrack just making sure.

8. Re: Heeelp linear algebraaa PLS :D

Originally Posted by He-Mann
I haven't done any computations but could you explain how you got r=(1,1,1) + s(1,0,1) + t(0,2,2) because this disagrees with my understanding of planes. Sorry for the backtrack just making sure.
named the points (1,1,1), (1,0,1) and (0,2,2) as PQR, did Q minus P and R minus P to find vectors u and v, denoted P(1,1,1) as ro
then from

r=r0+su+tv I plugged in results.

9. Re: Heeelp linear algebraaa PLS :D

Originally Posted by hayabusaboston
named the points (1,1,1), (1,0,1) and (0,2,2) as PQR, did Q minus P and R minus P to find vectors u and v, denoted P(1,1,1) as ro
then from

r=r0+su+tv I plugged in results.
Good but r=(1,1,1) + s(1,0,1) + t(0,2,2) = r0+sQ+tR != r0+su+tv.

10. Re: Heeelp linear algebraaa PLS :D

Originally Posted by He-Mann
Good but r=(1,1,1) + s(1,0,1) + t(0,2,2) = r0+sQ+tR != r0+su+tv.
The reason I am so broken up with my maths knowledge is because I dont revise much maths during semester I just lightly follow the lectures, I revise 2-3 weeks before the exam and thats when I start actually doing question booklets and past exams. I'm most comfortable doing that, and that gives me good results

But during the semester I will likely several times have broken knowledge and appear not to know the simplest shit for the simple reason I haven't sat down and focused on every concept in the framework i've only lightly glossed over it.

I should change this way of doing things I suppose.

Anyway is the cartesian equation x+2y-z=2, and (0,0,0) and (0,0,2) do NOT lie on the line? also for c), is the line L x-1=(y-1)/2=1-z?

11. Re: Heeelp linear algebraaa PLS :D

I can't brain atm how to do d) ahahah

12. Re: Heeelp linear algebraaa PLS :D

Also I have no idea how to do 2 c) because I don't understand what is meant by w-u,u,v and what to do with that tips plox?

13. Re: Heeelp linear algebraaa PLS :D

Originally Posted by hayabusaboston
The reason I am so broken up with my maths knowledge is because I dont revise much maths during semester I just lightly follow the lectures, I revise 2-3 weeks before the exam and thats when I start actually doing question booklets and past exams. I'm most comfortable doing that, and that gives me good results

But during the semester I will likely several times have broken knowledge and appear not to know the simplest shit for the simple reason I haven't sat down and focused on every concept in the framework i've only lightly glossed over it.

I should change this way of doing things I suppose.

Anyway is the cartesian equation x+2y-z=2, and (0,0,0) and (0,0,2) do NOT lie on the line? also for c), is the line L x-1=(y-1)/2=1-z?
So you found a strategy that yields impressive grades but has an immense drawback that you know will kill you in the future as mathematics is like building a tower, you can't go far with a weak foundation. I believe the problem with your strategy is that you believe too strongly of grades. It's not an effective measurement of how well you understand the course.

I've seen a lot of students in mathematics cram just to get good grades (HD) and falsely thinking they are somewhat of an expert at this course but they are no-where as good as the students who has studied the content with great depth but missed out some marks due to failed regurgitation.

Mathematics in university is still regurgitation, sadly, with the exception of some courses.

I think you should find another metric to evaluate 'success' in mathematics.

__________

I'm too lazy to do the computation. Also, r != (1,1,1) + s(1,0,1) + t(0,2,2)...

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