The parallel lines are drown on the plane. The distance between the lines is 2a. A needle of length 2l (l On a line segment OA with the length L of a numerical axis 0x are arbitrary marked two points...

The parallel lines are drown on the plane. The distance between the lines is 2a. A needle of length 2l (l <>

On a line segment OA with the length L of a numerical axis 0x are arbitrary marked two points B(x₁) and C(x₂). To find probability that it is possible to construct a triangle using three obtained segments.

In the sound detector the signals from two sources are received. An inflow of each of signals is equally possible at any moment of time interval by duration T. There is snap into action, if the difference between the arrival time of signals is equal t (t <>