**1. Why is the derived function of a function such as f(x) = c, where c is a constant, always 0.**

Because f(x) = c is a horizontal straight line whose

gradientis 0.

**2. Is it possible to differentiate an expression with brackets in.**

There are ways to differentiate with brackets still there but at this level it is simpler to expand them first.

**3. Is it possible to differentiate every function?**

Some parts of functions do not have a gradient.

e.g. In an

absolute valuefunction or a piecewise function if the graph is pointed, the gradient is not defined at that point.If a particular function is

not continuousi.e. You have to lift your pen off the paper when sketching the graph, it is not likely to have a gradient at that point.