(c) Integrate with respect to r, where A is a constant. () => 3. Differential Equations (a) From the differential equation (+) -m-0 find c(r) given D and m are constants, and the following boundary conditions Hint: see 2(c). (b) From the differential equation T-R de r =0 0 dr -kc-0 (0)- find c(r) given D and k are constants, and the following boundary conditions T=R CIC dc г=0 =0 dr Hint: use a substitution to solve differential equation. (c) Given the same differential equation as in part (b), find c(r) given the following boundary conditions T=R C=C T=00 c=0 Hint: for 3(b) and 3(c), select judiciously the appropriate general solution to differential equation. 4. Vector Algebra (a) Write out the expression for VCA = 0 in (i) cartesian. (ii) cylindrical, and (iii) spherical coordinates, where ca is a scalar. (b) For the time-dependent concentration field in cartesian space derive its gradient vector. CA-1-3z exp(-t-z²y + zy²)