I was not sure what was the independent variable in d). If it were x as in the previous items, then the function a = (7 - 22)^3 is a constant and its derivative = 0. So, da/db means that the derivative is taken by the variable b. The symbol [..] ' also means a derivative but does not specify by what variable.

Apr 17th, 2015

I was not sure what was the independent variable in d). If it were x as in the previous items, then the function a = (7 - 22)^3 is a constant and its derivative = 0. So, da/db means that the derivative is taken by the variable b. The symbol [..] ' also means a derivative but does not specify by what variable.