The equation of a curve is xy=12 and the equation of a line L is zx+y=k, where k is constant.
i) In the case k=11 find the coordinates of the points of intersection of L and the curve.
ii) Find the set of values of k for which L does not intersect the curve.
iii) In the case where k=10, one of the points of intersection is P(2,6). Find the angle in degrees between L and the tangent to the curve at P

Question

kainui · Answer

This is a fun one, what have you figured out so far or where are you stuck?

abmon98 · Answer

Should we solve it simultaneously

agent0smith · Answer

when k = 11

xy=12
zx+y=11

Use substitution to solve... is that z a constant?? It has to be for L to be a line.

agent0smith · Answer

Yes you should.

abmon98 · Answer

no z is not constant

agent0smith · Answer

Then how can L be a line?

abmon98 · Answer

good point but in ii it varies

abmon98 · Answer

could you please iam so stuck on that question

agent0smith · Answer

Question doesn't make a lot of sense. L can't be a line if z is a variable.

abmon98 · Answer

I dont know but thats whats writen in my textbook and this question is a pastpaper qustion from AS Maths Cambridge