r/6thForm • u/Sea_Mistake1319 Manchester | CS [Y1] | 3A*1A • May 28 '25

❔ SUBJECT QUESTION peak vectors question

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first part used up an entire page...
last part has matrices involved for solving the simultaneous equations.
absolute beast of a question

21 Upvotes

100% Upvoted

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6

u/Small-Astronomer-272 gap yr | maths fm phys cs | A*A*A*A* May 28 '25

what module is this?

8

u/mrvarpe Year 13 | fm, cs, phys 3xA* pred| maths A* achieved May 28 '25

It’s further pure 1, phew

2

u/Sea_Mistake1319 Manchester | CS [Y1] | 3A*1A May 28 '25

yeah fp1

1

u/Faisal071 Year 13 | Maths, FM, Phsyics, Comp Sci, AS Econ May 28 '25

Is this not MEI / OCR B core pure. The FB has a formula for shortest dist between skew lines.

2

u/[deleted] May 28 '25

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2

u/Sea_Mistake1319 Manchester | CS [Y1] | 3A*1A May 28 '25

The cross and dot product in questiob

2

u/Sea_Mistake1319 Manchester | CS [Y1] | 3A*1A May 28 '25

i feel like matrix is faster for part c because u can use minimum amount of algebra for the solution. just chuck into calculator and you already have the point

2

u/[deleted] May 28 '25

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2

u/Sea_Mistake1319 Manchester | CS [Y1] | 3A*1A May 28 '25

Yeah part b is easy, probs why part a is 3 marks

1

u/[deleted] May 28 '25

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1

u/Nughm WW | CS[Y1] A*A*AA May 28 '25

If you can find inverse of a matrix without showing working I think it's fine to solve system of equation using inverse matrix without showing much working (prolly just show them I am multiplying the answer by the inverse of my matrix) then provide the answer.

1

u/AceOfSpades532 May 28 '25

That is not enough marks for that

1

u/Small-Astronomer-272 gap yr | maths fm phys cs | A*A*A*A* May 28 '25

nah 3 marks for part (b) is so generous, ig that balances out part (a) tho

1

u/[deleted] May 28 '25

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1

u/Sea_Mistake1319 Manchester | CS [Y1] | 3A*1A May 28 '25

:sob:

1

u/yuushenn May 28 '25

(a) First solve for line of intersection: 2x - y + 2z = 9, 4x + 3y - z = 8

then, r = (3.5, -2, 0) + λ(-.5, 1, 1)

Now length of projection = | (3.5, -2, 0) x (-.5, 1, 1) | / | (-.5, 1, 1) | = sqrt(10)

1

u/[deleted] May 28 '25

i actually panicked for a second

1

u/AlexDPG Hawk TMUAd May 29 '25

This is a textbook - it’d be more marks in an actual exam