"Let y^2= 4ax be the equation of a parabola and (x1, y1) an external point P Then, equation of - Maths - Conic Sections

Question

"Let y^2= 4ax be the equation of a parabola and (x1, y1) an
external point P Then, equation of the tangents is given by?

SS1= T^2,where S = y^2-4ax, S1= y1^2- 4ax1, T = yy1 2a(x-x1)"?
How is the equation tangent given by SS1=T^2 ?

Aarushi Mishra · Accepted Answer

"Let y^2= 4ax be the equation of a parabola and (x1, y1) an external point P. Then, equation of the tangents is given by? SS1= T^2,where S = y^2-4ax, S1= y1^2- 4ax1, T = yy1 2a(x-x1)"? How is the equation tangent given by SS1=T^2 ?