Find the time an aeroplane having velocity `v` takes to fly around a square with side `a` if the wind is blowing at a velocity `u` along one side of the square.\

Answer

[(a) `2a (v + sqrt(v^(2) - u^(2))/(v^(2) - u^(2)))`, (b) `2 sqrt2 a ((sqrt(2v^(2) - u^(2)))/(v^(2) - u^(2)))`]