The angle between the tangents drawn from the point (−a,2a) to y2=4ax is
(−a,2a)
y2=4ax
y=mx+am is tangent to parabola y2=4ax
it is pass through point (−a,2a)
2a=−ma1+am
m2a+2am−a=0
m2+2m−1=0
m=−1±√2
m1=√2−1,m2=−√2−1
m1+m2=2
m1.m2=−1
m1−m2=2√2
tanθ=|m1−m21+m1.m2|
tanθ=2√20=∞
θ=π2