i can't understand example 2 please explain me briefly and fastt
Here is the answer to your query.
Let us imagine AB acts as a mirror. Then P' is the position of image of point P.
Let us join P' and Q by a straight line which passes through the wall at point R.
Since the object and its mirror image are at the same distance from the mirror.
∴ P and P' are at the same distance from the wall
⇒PR = P'R ... (1)
Now the shortest distance between P' and Q is P'Q and P'Q = P'R + RQ
⇒ P'Q = PR + RQ (From (1))
Hence the path from P to R and then from R to Q is the shortest path when should be followed by Sanjana.