Parametrics question (2 Viewers)

[nazfiz]

Im having problems with question 4 part ii part alpha. The answers just say if y=a. Then pq=1

Thanks for any help

 

[Carrotsticks]

Substitute the point (a,0) into the equation of the line PQ, and you will get the result.

 

[Timske]

<a href="http://www.codecogs.com/eqnedit.php?latex=A ( a(p@plus;q) , apq) ~ S(0,a) \\\\ Gradient~ of~ AS = \frac{apq-a}{a(p@plus;q)} \\\\ \frac{apq-a}{a(p@plus;q)} = 0 \\\\ apq - a = 0 \\\\ a(pq-1)=0 \\\\ pq = 1" target="_blank"><img src="http://latex.codecogs.com/gif.latex?A ( a(p+q) , apq) ~ S(0,a) \\\\ Gradient~ of~ AS = \frac{apq-a}{a(p+q)} \\\\ \frac{apq-a}{a(p+q)} = 0 \\\\ apq - a = 0 \\\\ a(pq-1)=0 \\\\ pq = 1" title="A ( a(p+q) , apq) ~ S(0,a) \\\\ Gradient~ of~ AS = \frac{apq-a}{a(p+q)} \\\\ \frac{apq-a}{a(p+q)} = 0 \\\\ apq - a = 0 \\\\ a(pq-1)=0 \\\\ pq = 1" /></a>

 

[Timske]

Substitute the point (a,0) into the equation of the line PQ, and you will get the result.

Is it (0, a) or can it be (a, 0 )

 

[Carrotsticks]

Is it (0, a) or can it be (a, 0 )

It's in the form x^2=4ay, so it can either be (0,a) or (0,-a).

But usually, they have a>0 for simplicity's sake.

 

[Timske]

It's in the form x^2=4ay, so it can either be (0,a) or (0,-a).

But usually, they have a>0 for simplicity's sake.

ok