Has anyone proved that y=2y zero on that problem in the first lecture where he used symmetry to get that y=2y zero? Could you help because I keep getting y=2/x zero.

Question

Has anyone proved that y=2y zero on that problem in the first lecture where he used symmetry to get that y=2y zero?  Could you help because I keep getting y=2/x zero.

stacey · Answer

I would need to see the actual problem.

anonymous · Answer

y-y zero=-1/(x zero)^2 (x-x zero) is the problem.  The professor solved for x by plugging in y=0 and got x=2x zero which I understand.  Then he said by symmetry you get y=2y zero and we could prove it by taking the same equation and plugging in x=0.  Every time I do that, I get y= 2/x zero, not y=2y.

stacey · Answer

Based on what you are saying, I am assuming that previously in the lecture, it was stated that $$y _{0} = -\frac{ 1 }{ x _{0} }$$If that is the case, then $$x _{0} = -\frac{ 1 }{ y _{0} }$$ and $$y=2y _{0}$$

anonymous · Answer

i must be doing something wrong...thanks anyway

anonymous · Answer

The area of the triangle as he derives is 2XoYo. As y = f(x) = 1/X, f(Xo) = 1/Xo. Therefore Yo = 1/Xo. Thus, 2XoYo = 2Xo(1/Xo) = 2