amaths!!!!!

(a)
sub y=0 into H
we get a=3
sun x=5 into H
we get b=8/3
(b)
The tangent line for the x^2/a^2-y^2/b^2=1 at (x1,y1) is
xx1/a^2-yy1/b^2=1
So the equation of L is
5x/9-(8/3)y/4=1
5x/9-2y/3=1 or
5x-6y=9


2007-12-26 14:14:03 補充：
hyperbola 的切線方程可以在pure maths 書中找到證明。