If an equation has the form c = A + Bt - Ct^2 + Dt^3 + Ez Where A,B,C,D and E are known constants, t and z are the variables. t=15 and z=2. Derive an algebraic expression for delta_c/c in terms of delta_z/z and delta_t/t. Apparently you are suppose to calculate delta_z, delta_t and delta_c and then use your value for c (which was calculated using the values of z and t) to get a value for delta_c/c but i haven't a clue where to start. Any advice would be much appreciated..