6. The derivative of a function ƒ at a number a denoted by ƒ'(a), is

ƒ'(a)= lim→f(a+h)-f(a)/h if this limit exists.Sketch f(x) = x² and draw a representation that shows the relationship between f'(a), f(a+h)and f(a). Explain how your illustration represents the definition of the derivative a function at a number a.