The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

FP3 Maths OCR Question (Vectors)

On the June 2010 FP3 OCR Past paper, On question 7 part iii it states to use k as being 4, but allows k as being 4 root 21, which is what I used. The final part uses k = 4, and was wandering if anybody could explain why? Thank you.
Reply 1
Avatar for Zacken
Zacken
22
Original post by sarahemilyglass
On the June 2010 FP3 OCR Past paper, On question 7 part iii it states to use k as being 4, but allows k as being 4 root 21, which is what I used. The final part uses k = 4, and was wandering if anybody could explain why? Thank you.


The perpendicular to the plane through (-7, -3, 0) meets the plane at (−7+k)+4(−3+4k)+2(2k)=23  ⟺  k=2(-7+k) + 4(-3 + 4k) + 2(2k) = 23 \iff k =2

So you need to double that, not double the distance.
Original post by Zacken
The perpendicular to the plane through (-7, -3, 0) meets the plane at (−7+k)+4(−3+4k)+2(2k)=23  ⟺  k=2(-7+k) + 4(-3 + 4k) + 2(2k) = 23 \iff k =2

So you need to double that, not double the distance.


Ahh I understand thank you! Spent all day learning/revising vectors so think I reached my limit for the day haha :smile:
Reply 3
Avatar for Zacken
Zacken
22
Original post by sarahemilyglass
Ahh I understand thank you! Spent all day learning/revising vectors so think I reached my limit for the day haha :smile:


Awesome! No problem, hope it was a productive day. :smile:

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you