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# C4 Vectors Watch

1. page 12 question 4 part C, 'find the distance of the point B from the line l1'

in the mark scheme it assumes that the angle AB makes with l1 is 90 degrees i think, but don't see why. Could someone please explain?
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2. C4 Solomon exam style questions - solutions.pdf (424.5 KB, 123 views)
3. C4 Solomon exam style questions.pdf (457.2 KB, 2653 views)
4. (Original post by TPJY)
page 14 question 4 part C, 'find the distance of the point B from the line l1'

in the mark scheme it assumes that the angle AB makes with l1 is 90 degrees i think, but don't see why. Could someone please explain?
The Q4 (c) on page 14 asks you to show that two vectors are perpendicular.

There are no lines involved.
5. (Original post by Indeterminate)
The Q4 (c) on page 14 asks you to show that two vectors are perpendicular.

There are no lines involved.
sorry i meant page 12
6. (Original post by TPJY)
sorry i meant page 12
I can't see how the MS assumes that AB is perpendicular to l1.

They have just used the area of the triangle (half the area of the parallelogram) to find the distance.

7. (Original post by Indeterminate)
I can't see how the MS assumes that AB is perpendicular to l1.

They have just used the area of the triangle (half the area of the parallelogram) to find the distance.

ahhhh okay i see now thanks!

could i ask i you could explain what they do in their mark scheme for question 7 page 13 part C please? i don't really see why they find |3,-2,2|
8. bump

could someone help me with question 7c, page 13? im still not getting it ;(
9. (Original post by TPJY)
bump

could someone help me with question 7c, page 13? im still not getting it ;(
Having worked out the distance PQ, we know this to be the same as QR.

QR lies entirely on l2, and will be a scalar multiple of that line's direction vector.

By working out the length of the direction vector we can determine what the scalar multiple is; in this case 2.

OR = OQ +/- 2"direction vector of l2"
10. (Original post by ghostwalker)
Having worked out the distance PQ, we know this to be the same as QR.

QR lies entirely on l2, and will be a scalar multiple of that line's direction vector.

By working out the length of the direction vector we can determine what the scalar multiple is; in this case 2.

OR = OQ +/- 2"direction vector of l2"
thank you very much!
11. (Original post by TPJY)
page 12 question 4 part C, 'find the distance of the point B from the line l1'

in the mark scheme it assumes that the angle AB makes with l1 is 90 degrees i think, but don't see why. Could someone please explain?
Thanks for the questions!

12. (Original post by TPJY)
page 12 question 4 part C, 'find the distance of the point B from the line l1'

in the mark scheme it assumes that the angle AB makes with l1 is 90 degrees i think, but don't see why. Could someone please explain?
do you have c3 solomon exam style questions by any chance?

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