Parametrics (1 Viewer)

[tennille]

This is from the 2001 HSC paper (question 6).

Find the coordinates of Q on the parabola such that the normal at Q is perpendicular to the normal at P (the gradient of the normal P is -1/t).

Find the equation in cartesian form of the locus of the point R. (the coordinates of R is (a(t - 1/t), a (t^2 + 1 + 1/t^2) ). For this question, I don't how how to eliminate t.

 

[Jase]

square the x to get an expression for t^2 + 1/t^2

 

[jumb]

i got y = (x^2 +3a)/a

 

[tennille]

Okay. Thank you so much. I got the same as you Jumb. I just need help with the first question, because that is needed to determine the locus. I hate questions that have many parts to it, and if you don't know the first question, you can't do the others.

 

[Managore]

This is how you solve problems including the third variable

*stabs third variable with a knife*

 

[jumb]

Remember to use that tomorrow.