Show that there does not exist any real number c such that the following function f(x) would be a valid probability density function: f(x) = ( c=(1 + x); if x > 0 0; otherwise: Repeat if f(x) were given by: f(x) = ( c=(x); if x > 0 0; otherwise: Hint: To be a valid density function f must be non-negative and integrate to 1.