1. The problem statement, all variables and given/known data From Ashby's "Engineering Materials" 2. Relevant equations [itex]k=C_o/C_s=m_1/m_2[/itex] 3. The attempt at a solution Solving for k [itex]m_1=(660-548)/(0-32)=-3.5[/itex] [itex]m_2=(660-548)/(0-7)=-16[/itex] [itex]k=m_1/m_2=0.219[/itex] [itex]C_s=C_o*(1-(1-0.219)exp(-xL/0.219))[/itex] How do I proceed from there? Also, how do I incorporate the [itex] C_l [/itex] term in the equation? Thanks!