1. The problem statement, all variables and given/known data A particle is trapped in an infinite one-dimensional square well which extends between x=0 and x=a. If the particle is in the ground state, calculate the probability that it is between 0.4a and 0.6a. 2. The attempt at a solution The normalised of the ground state is sqrt((2/a)sin(pi*x/a) Setting k = pi/a, I get the probability (2/a)Int(sin^2(kx)dx for 0.4 - 0.6. How can I solve this integral?