Can anyone help with these problems? I have no idea where to start. What is the general approach? Determine the solution of ∂ρ/∂t = (sin x)ρ which satisfies ρ(x,0) = cos x. Determine the solution of ∂ρ/∂t = ρ which satisfies ρ(x,t) = 1 + sin x along x =-2t. Relevant equations: ∂ρ/∂t + ∂/∂x(q(ρ)) = 0 or ∂ρ/∂t + ∂/∂x(ρu(ρ)) = 0 and q = ρu.