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\(y-{p}^{2}x = \frac{5}{p}-5{p}^{3}\) crosses the line \(y = -x\) at point A

 

Show that point A is \(\left ( \frac{5}{p}-5{p}^{3},-\frac{5}{p}+5{p}^{3} \right )\)

 

This was the last question in my further maths paper, couldn't do it

 May 20, 2016
edited by Guest  May 20, 2016
 #2
avatar+33653 
+5

Replace y by -x

 

-x - p^2*x = 5/p - 5p^3

 

-x*(1 + p^2) = (5/p)*(1 - p^4)

 

-x*(1 + p^2) = (5/p)*(1 + p^2)*(1 - p^2)

 

-x = (5/p)*(1 - p^2)

 

x = -5/p + 5p

 

Hence y = 5/p - 5p

 

Hmm, doesn't match your desired solution!

 May 20, 2016
 #3
avatar+129840 
0

I got the same result as Alan did.....as a check......

 

y - p^2x   .......     let x = 5p - 5/p  .....    and let y = -x      ....   and we have....   

 

[5/p - 5p] - p^2 [ 5p - 5/p]  =

 

5/p - 5p - 5p^3 + 5p  =

 

5/p - 5p^3       and this  =  the right side

 

So.......the solution should be :

 

(x , y)   =   ( 5p - 5/p ,  5/p - 5p )

 

 

cool cool cool

 May 20, 2016

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