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# P6 ... say what ? ... watch

1. 7a was worded quiet awkwardly. I assumed that |W|=1, then as normal worked ot that y=x, i.e argument(Pi/4). How did you do the matrix question? I got k as 18, p as 3, a as 1, b as 4 and c as -1. The determinant with these values was zero though which doesn't seem right.
2. (Original post by 786)
7a was worded quiet awkwardly. I assumed that |W|=1, then as normal worked ot that y=x, i.e argument(Pi/4). How did you do the matrix question? I got k as 18, p as 3, a as 1, b as 4 and c as -1. The determinant with these values was zero though which doesn't seem right.
k was 18, p was 3 then simultaneous equations to get b^2 = 18, hence find a, b, c noting that a>0. The determinant clearly cantt be zero as M would be singular but M^-1 = 1/18 M^T so M is non-singular
3. (Original post by Bezza)
Determinant is area/volume scaling factor so I don't think it should be negative as you can't have a negative area/volume
its rite ... i got it 2 ... but they asked for the modulus of the det .... unless im forgetting sumthing important

p=3
k=18
a b c ... i dont remember which one was which ... but one was 2root2 root2 and -2root2 ...

i have a graphic calc and i chcek it useing the matrice funsction ...the answers work like a charm ...
4. (Original post by Bezza)
Determinant is area/volume scaling factor so I don't think it should be negative as you can't have a negative area/volume
how about the determinant of -1I where I is the identity matrix?
5. What answers you got for the first question?
6. (Original post by A2 student)
What answers you got for the first question?
remind me wat it was ?
7. (Original post by Bezza)
Determinant is area/volume scaling factor so I don't think it should be negative as you can't have a negative area/volume
Is it like Integration where you have a given area that is under the x-axis, hence when you calculate this you need to ignore the -ve sign and take the number value as the actual area?
8. (Original post by infekt)
its rite ... i got it 2 ... but they asked for the modulus of the det .... unless im forgetting sumthing important

p=3
k=18
a b c ... i dont remember which one was which ... but one was 2root2 root2 and -2root2 ...

i have a graphic calc and i chcek it useing the matrice funsction ...the answers work like a charm ...
2root2, -root2 and -2root2
9. (Original post by Checkey)
Is it like Integration where you have a given area that is under the x-axis, hence when you calculate this you need to ignore the -ve sign and take the number value as the actual area?
it was given in the paper " | det M | "
10. (Original post by keisiuho)
2root2, -root2 and -2root2
possbly ...
wait ... i think i still have the matric saved in my calc ... lemme take a look at it
11. (Original post by A2 student)
What answers you got for the first question?
26660?
12. (Original post by keisiuho)
26660?
tht was p4 mate
13. (Original post by keisiuho)
how about the determinant of -1I where I is the identity matrix?
Determinant is just 1 because it doesn't change the area/volume. I just got 54sqrt2 straight out anyway so it didn't affect me!!
14. man the matrice is saved but its all in decimals in the calc ... im too lazy to do it again .. im jus happy skools over
15. (Original post by infekt)
tht was p4 mate
oh sorry

2.06 and 2.13
16. (Original post by keisiuho)
oh sorry

2.06 and 2.13
yup .. .hehe .. keep making me happy keisiuho
17. (Original post by Bezza)
Determinant is just 1 because it doesn't change the area/volume. I just got 54sqrt2 straight out anyway so it didn't affect me!!
isnt it (-1)x(-1)x(-1)=-1?
18. I got something like that too
19. (Original post by infekt)
yup .. .hehe .. keep making me happy keisiuho
P4 again?
20. no ... ur answers match mine ... i thought i did badly .. well i did .. but ill manage a 50 / 75

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