Derive an algebraic expression

[garyman]

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..

 

[HallsofIvy]

Yes, first calculate c when t= 15 and z= 2. Then do the same thing except use t= 15+ deltat, z= 2+ deltaz so you get a another value of c which will depend on deltat and deltaz. deltac will be the difference between those two values and deltac/c is that difference divided by your first value for c.