1. The problem statement, all variables and given/known data write the following in K basis: A=∫|x><x|dx where the integral limits are from -a to a 2. Relevant equations 3. The attempt at a solution I tried solving it by inserting the identity I=∫|k><k|dk where the integral limits are from -∞ to +∞ but then I do not know how to proceed from there. What to do about the two integrals with varying limits!