Question

Level 3 question - locus again

Answer 1

lol, I forgot to delete something :S

Answer 2

Hmm Co-ordinate of Q be (b,0) and P (b,a).
Equation of L is 3x + 4y + 14= 0. So, 3b + 4a + 14 = 0 (1). You have the relation for a and b now. \[N\equiv \left(b,\frac{2a}5\right)\]
\[x = b\tag2\]\[5y = 2a\tag3\]
Now solve the equations 1,2 and 3.

Answer 3

Is Chinese Cartesian system different?

Answer 4

Why you asked that question?

Answer 5

While I defined Q as (b,0). She defined it as (0.b).
http://assets.openstudy.com/updates/attachments/4f8be056e4b0935d57e9b307-callisto-1334567021212-math.jpg

I should say co-ordinate system, right? Because the one we follow is Cartesian co-ordinate system.

Answer 6

Q is (0,b) ...

Answer 7

*facepalm* :(

Answer 8

*epic facepalm*
My co-ordinate points aren't right but the concept is right you should use the concept.

Answer 9

Or, N is now (2a/5,b) and the relation between a and b is 3a + 4b = 14. Maybe.

Answer 10

BTW, that wasn't my workings...

Answer 11

Can I do it in this way?
Let N=(x,y) , Q = (0,b)
Since P is perpendicular to Q, y coordinate of P =b
Put y=b into 3x+4y+14 =0
3x + 4b +14 =0
x = (-4b-14)/3
So, P = [ (-4b-14)/3 , b]
By section formula
[(-4b-14)/3 ] x3 + 0 x2
------------------- =x
5
(-4b-14) =5x
b = (5x+14)/(-4)

b x3 + b x2
----------- =y
5
y = b = (5x+14)/(-4)
Therefore, the equation is
y =(5x+14)/(-4)

Answer 12

i'm doing it differently but yours looks good...

Answer 13

What's the way you're using?

Answer 14

i'm using distance like the ellipse locus earlier...

Answer 15

Basically, I just 'copied' the way I did for the previous locus problem

Answer 16

lol

Answer 17

and that's what i'm doing with my previous one too..

Answer 18

***this one

Answer 19

This time, you'll probably give an elegant solution like last time :)

Answer 20

dunno... my "y" keeps vanishing!

Answer 21

3a + 4b = - 14, N (x,y) \(\equiv \left(\frac{2a}5, b\right)\)
\[3 a\frac22 \cdot \frac55 + 4\cdot b = 14\implies \frac52 \cdot 3x + 4y +14=0 \]Is this wrong?

Answer 22

/_\ .... @Ishaan94 you know you're always better than me.... and I dare not challenge you....:(

Answer 23

So the answer is not matching, let me check it again. I commit lots of silly mistakes. :/

Answer 24

read this attach file..

Answer 25

Hmm Callisto was right and I wrong.