Question

From the point (-2, -4), tangents are drawn to the parabola x² = 4y, then the equation of chord of contact is
O x-y+ 4 = 0
O x + y -4 = 0
O x + 2y - 8 = 0
O x-2y + 8 = 0​

Answer 1

Answer:

The correct answer is $x+y-4=0$

Step-by-step explanation:

We know that equation of chord of contact to any conic is given by

                                         $\boxed{\text{T}=0}$

Here the parabola is $x^2=4y$ and the point is $(-2,-4)$

So the equation of chord of contact is  

 $\Rightarrow \text{T}=0\Rightarrow xx_1=4(\frac{y+y_1}{2})\\\\\Rightarrow x(-2)=2(y-4)\\\Rightarrow -x=y-4\\\Rightarrow x+y=4$