Please see the attached file for the fully formatted problems.
Let f(x) = sqrt of x, and show that in this case (f(x+h)-f(x))(f(x+h)+f(x))=h.
Use this result to give a simplified expression for f(x+h)-f(x)/h.
When f(x) = sqrt x what is lim h-->0 f(x+h)-f(x)/h ?
An expression is simplified and a limit is found. The solution is detailed and well presented.