Hi! Define an integral operator K: L^2 (0,1) -> L^2(0,1) by: Kx(t) = Integral[ (1+ts)exp(ts)x(s) ds from t=0 to t=1]. Why is "obvious" that K is a one-to-one operator? I know K is one to one if Kx(t) = 0 implies x(t) = 0 but I don't see why this is true. Can you please explain why?