Hard maths question need help Watch

ccc8
Badges: 6
Rep:
?
#1
Report Thread starter 1 week ago
#1
part c) is what im having issue with, i have found k < 37/4, but have no clue how to find the other value, which is meant to be k=7?
Last edited by ccc8; 1 week ago
0
reply
ccc8
Badges: 6
Rep:
?
#2
Report Thread starter 1 week ago
#2
bump
0
reply
Pangol
Badges: 12
Rep:
?
#3
Report 1 week ago
#3
(Original post by ccc8)
part c) is what im having issue with, i have found k < 37/4, but have no clue how to find the other value, which is meant to be k=7?
If you managed to draw the sketch in (b)(i), you'll know that you have a portion of a parabola. Now consider the line x + y = k drawn on the same graph. You should be able to see that there are only certain positions where the line intersects the parabola in two places. You have found one condition on k for this to happen - that's the condition for the line not to be too "far up". But you should also be able to see that if the line moves too "far down", it will only intersect the parabola at one point.

The limiting case is where the line passes through the right-hand endpoint of the parabola. Take the coordinates of this point, plug them into the equation of the line, and see what you get.
1
reply
ccc8
Badges: 6
Rep:
?
#4
Report Thread starter 1 week ago
#4
oh i completely understand now thank you
(Original post by Pangol)
If you managed to draw the sketch in (b)(i), you'll know that you have a portion of a parabola. Now consider the line x + y = k drawn on the same graph. You should be able to see that there are only certain positions where the line intersects the parabola in two places. You have found one condition on k for this to happen - that's the condition for the line not to be too "far up". But you should also be able to see that if the line moves too "far down", it will only intersect the parabola at one point.

The limiting case is where the line passes through the right-hand endpoint of the parabola. Take the coordinates of this point, plug them into the equation of the line, and see what you get.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

University open days

  • Cardiff University
    Undergraduate Open Day Undergraduate
    Wed, 27 Mar '19
  • University of Portsmouth
    Postgraduate and Part-Time Open Evenings Postgraduate
    Wed, 27 Mar '19
  • Middlesex University London
    Postgraduate Open Evening Postgraduate
    Wed, 27 Mar '19

How old were you when you first saw porn?

I've never seen it (59)
21.77%
Before I was 12 (96)
35.42%
13 (41)
15.13%
14 (39)
14.39%
15 (19)
7.01%
16 (5)
1.85%
17 (2)
0.74%
18 (3)
1.11%
Between the ages of 19 - 24 (4)
1.48%
Over 25 (0)
0%
12 (3)
1.11%

Watched Threads

View All