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A pair of tangents are drawn from the origin to the circle `x^2 + y^2 + 20 (x + y) + 20 = 0`, The equation of pair of tangent is

Answer» Correct Answer - `2x^(2)+2y^(2)+5xy=0`
We have `S=x^(2)+y^(2)+20x+20y+20=0`
Equation of pair of tangents from origin is given by `T^(2) S S_(1)`.
or `(0.x+0.y+10(x+0)+10(y+0)+20)^(2)`
`=(x^(2)+y^(2)+20x+20y+20)(20)`
or `5(x+y+2)^(2)=(x^(2)+y^(2)+20x+20y+20)` or `2x^(2)+2y^(2)+5xy=0`


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