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September 13, 2025, 07:31:42 am

Author Topic: Uni Maths Questions  (Read 34767 times)  Share 

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Re: Uni Maths Questions
« Reply #90 on: June 03, 2013, 09:24:24 pm »
0
How do I do this question?

Find all solutions in mod 2 of the following linear system:
x1  +  x3         + x5 = 1
x1  +  x3 + x4 + x5  = 0
                 x4 + x5  = 0

Express your answer as a finite list.

So I've put the system into an augmented matrix and reduced it to RREF:
1 0 1 0 1 | 1
0 0 0 1 0 | 1
0 0 0 0 1 | 1

How do I find the solutions from here? Thanks

Mao

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Re: Uni Maths Questions
« Reply #91 on: June 04, 2013, 12:21:26 am »
+2
The full RREF in is
Code: [Select]
1 0 1 0 0 0
0 0 0 1 0 1
0 0 0 0 1 1

x1=t, x2=s, x3=t, x4=1, x5=1,   
« Last Edit: June 04, 2013, 11:51:38 pm by Mao »
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M-D

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Re: Uni Maths Questions
« Reply #92 on: June 04, 2013, 03:39:55 pm »
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how can i express the following in Cartesian form a+ib:



the answer in the solutions is

thanks

mark_alec

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Re: Uni Maths Questions
« Reply #93 on: June 04, 2013, 03:44:13 pm »
+2
Since this is university maths, I assume you have come across the identity:
.

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Re: Uni Maths Questions
« Reply #94 on: June 04, 2013, 03:46:32 pm »
0
That RREF isn't right. It should be
Code: [Select]
1 0 1 0 0 0
0 0 0 1 0 -1
0 0 0 0 1 1

The answer is x1=t, x3=-t, x4=-1, x5=1,

I thought in mod 2 there are only two numbers 0 and 1?

M-D

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Re: Uni Maths Questions
« Reply #95 on: June 04, 2013, 04:46:37 pm »
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Since this is university maths, I assume you have come across the identity:
.

could you show me the working out please. thanks

mark_alec

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Re: Uni Maths Questions
« Reply #96 on: June 04, 2013, 04:47:47 pm »
+1
Use that identity and the usual index law:

Alwin

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Re: Uni Maths Questions
« Reply #97 on: June 04, 2013, 05:00:03 pm »
+3
Since this is university maths, I assume you have come across the identity:
.
could you show me the working out please. thanks

Hmm, M-D I'm not sure if you're doing Uni Maths, or UMEP. Perhaps clarifying would help :)

Anyways, from Complex Numbers in the UMEP course:

To Prove:


Let:


Hence:








This is a constant function, since gradient = 0

Also,


Thus:






As Required :)
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Re: Uni Maths Questions
« Reply #98 on: June 04, 2013, 05:06:51 pm »
+1
could you show me the working out please. thanks


Hmm, M-D I'm not sure if you're doing Uni Maths, or UMEP. Perhaps clarifying would help :)



There's a difference?  ???
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Alwin

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Re: Uni Maths Questions
« Reply #99 on: June 04, 2013, 05:12:30 pm »
+2
There's a difference?  ???

Hmm, not really. Just that our course, MAST10013 UMEP Mathematics for High Achieving Students is actually only a 1 semester subject at Melbourn University haha.

Just wasn't sure what Maths M-D does in uni, like pure maths and statistics-based maths would vary by a LOT :P


EDIT: Deleted 2nd post, just added it here:
how can i express the following in Cartesian form a+ib:



the answer in the solutions is

thanks
AHAHAHAHAHAHA SORRY M-D I did't actually answer your question.

So, you have the identity:
  See my other post, Re: Uni Maths Questions, if you still want the formal proof.

Continuing, so you now have:








TADAAAA :D
« Last Edit: June 04, 2013, 05:25:43 pm by Alwin »
2012:  Methods [48] Physics [49]
2013:  English [40] (oops) Chemistry [46] Spesh [42] Indo SL [34] Uni Maths: Melb UMEP [4.5] Monash MUEP [just for a bit of fun]
2014:  BAeroEng/BComm

A pessimist says a glass is half empty, an optimist says a glass is half full.
An engineer says the glass has a safety factor of 2.0

M-D

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Re: Uni Maths Questions
« Reply #100 on: June 04, 2013, 07:16:25 pm »
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thanks Alwin. how to do get the theta and phi symbols in Latex?

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Re: Uni Maths Questions
« Reply #101 on: June 04, 2013, 07:31:09 pm »
+2
thanks Alwin. how to do get the theta and phi symbols in Latex?
\phi \Phi
\theta \Theta

The case of the first letter alternates between upper or lowercase. You'd be using the lowercase ones in this case.

If you click 'quote post' on a post with latex, you can look through the latex code they used that way too. (Or right click -> open image in new tab and read the latex code from the URL).

Mao

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Re: Uni Maths Questions
« Reply #102 on: June 04, 2013, 11:47:05 pm »
+1
I thought in mod 2 there are only two numbers 0 and 1?

Oops, I didn't even read the question. I'll update the answer.
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Mao

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Re: Uni Maths Questions
« Reply #103 on: June 04, 2013, 11:57:44 pm »
+5
So, you have the identity:
  See my other post, Re: Uni Maths Questions, if you still want the formal proof.

Continuing, so you now have:








TADAAAA :D

At this level, it's probably more intuitive to stay away from :

« Last Edit: June 04, 2013, 11:59:22 pm by Mao »
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Re: Uni Maths Questions
« Reply #104 on: June 06, 2013, 09:43:06 pm »
0
Thanks Mao!

Could someone help me with this question as well?

Without having to find the linear transformation matrix, how do I calculate the dimensions of the image and kernel for the linear transformation:

R: R^3->R^3 by reflection in the plane x+y+z=1 ?

So I know that dim(Ker) = nullity of R and dim(Im) = rank of R but I don't know whether these facts are of any use in this question?


« Last Edit: June 06, 2013, 09:44:56 pm by Deleted User »