Let f(x) = √x.

Using the definition of derivative at a point, f'(a) = limₓ→ₐ (f(x) - f(a))/(x - a), enter the expression needed to find the derivative at x = 4, as well as the equation of the tangent line.

f'(4) = limₓ→₄ _____________

After evaluation this limit, we see that f'(4) = _____