Question

Find the equation of pair of tangents drawn to the circle $x^2+y^2-4x+4y=0$ from the point (2, 2)

• A.
• B.
• C.
• D.

Answer 1

The correct option is C

Given circle is,

$x^2+y^2-4x+4y=0,$

and external point is (2, 2) we have to use the formula

$S{S}_1=T^2$

$[x^2+y^2-4x+4y][4+4-8+8]=2x+2y-2(x+2)+2(y+2)$

$8.[x^2+y^2-4x+4y]=2y+2y-4+4$

$4.[x^2+y^2-4x+4y]=4y$

$4x^2+4y^2-16x+12y=0$