If two tangents are made from the point p (3,2) outside the circle to the circle, the distance from the point p to the center m is equal to the root number 5.

The tangent value of the included angle between each tangent and pm is equal to 1/2,

Therefore, the tangent value of the included angle between two tangents is tan θ = (2 *1/2)/(1-kloc-0//4) = 4/3, and the cosine value of the angle is equal to 3/5.

2 stands for square.

Let the angle between the two tangents and pm be a..

Then tana= 1/2

The included angle between the two tangents is a=a+a=2a.

So tana = tan2a = 2tana/(1-tan2a)

=(2* 1/2)/( 1- 1/4)=4/3