The tangents drawn from the origin to the circle #x^2 + y^2 -2rx -2hy +h^2=0# are perpendicular if?
A) #h=r#
B)#h=-r#
C) #r^2+h^2=1#
D) #r^2+h^2=2#
A)
B)
C)
D)
1 Answer
Oct 20, 2017
Both (A) and (B).
Explanation:
The center of circle
As
Further, as we are drawing tangent from origin i.e.
As such, distance from center
Hence answer could be both (A) and (B).
As an example see the following graph.
graph{((x-5)^2+(y-5)^2-25)((x-5)^2+(y+5)^2-25)=0 [-19.92, 20.08, -9.76, 10.24]}