mid point question
(x1+x2/2,y1+y2/2) Is that it?
no one sec
Suppose the tangent line at a point P on the hyperbola xy = 3, cuts the x-axis at point A and the y-axis at point B.
Show that P is the mid-point of the line segment AB.
first find the equation of the tangent line, it doesnt matter if there are extra variables, then prove that 1/2 the x coordinate of A and 1/2 the y coordinate of B are the same as the x and y coordinates of P, showing that P is the midpoint
Hint. The point P on the hyperbola takes the form P = (a; 3=a) for some non-zero a.
sorry if thats not very clear, assign variables to the x and y coordinates of P and remember that xy=3, and it will simplify and work out
P(a,3/a)**
yeah, now find the equation of tangent line at P using that and the derivative of xy=3
ok ty
w8 then what do u do?
i get L(x)=3/x + -3/x^2 (x-a) for the equation of the tangent
well actually 3/a + -3/a^2 (x-a)
then what?
find where it intersects the y and x axes, if you put it in slope intersect form you know the y axis intercept, to find the x intercept set y=o and solve for x
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