Question

Two tangents are drawn from a point( -4,3) to the parabola y^2 =16x.If alpha is the angle between them then the value of cos alpha is

Answer 1

Answer:

y=mx +4/m  is the general from tangent to  this parabola  it will also pass throw point -4,3 so putting the value we get two vale of m (slope),

now tan(alfa)= (m2-m1)/1+m1*m2