Find the length of the tangent from a point (6, 1) to the circle x2+y2−4x=0.
5
4
Method (1)
Given circle is x2+y2−4x=0
Std form (x−2)2+y2=4
Centre ≡(2,0)
Radius = 2 units
∴(Tangent length)2=PC2−CT2
=√42+122−radius2
=17−4
=13
=√13 units.