Two tangent are drawn from the point `(-2,-1)` to parabola `y^2=4xdot` if `alpha` is the angle between these tangents, then find the value of `tanalphadot`

Explanation

Here a=1. Any tangent having slope m is `y=mx+(1)/(m)`
It passes through (-2,-1). Therefore,
`2m^(2)-m-1=0`
`orm=1,-(1)/(2)`
So, `tanalpha=(1+(1//2))/(1-(1//2))=3`