Science:Math Exam Resources/Courses/MATH100/December 2010/Question 06/Hint 1

The definition of a derivative is

$\displaystyle f'(x)=\lim _{h\to 0}{\frac {f(x+h)-f(x)}{h}}$

Alternatively, one can use

$\displaystyle f'(a)=\lim _{x\to a}{\frac {f(x)-f(a)}{x-a}}$