According to Heisenberg Uncertainty principle,
Del(X)xdel(P) >= h/2(pi)
But there is also another expression given in my book which is,
Del(X)xdel(P) >= h/4(pi)
I asked my lecturer why is it so? She said that, the second expression is obtained from Fourier analysis. But she also said that in calculations, you can use the first one. Which should I use in competitive exams?