1. Find an equation of the tangent line to the curve y = 9x at the point (1, 9).

2. A water storage container starts leaking at time t = 0 minutes. The water leaks out from the container at a rate of f(t) = 10e ^0.1t litres per minute. Find the amount of water that leaks out during the first hour.

3. Let g(x) be a differentiable function and let p be a positive constant. For f(x) = p ^g(x) , find the derivative of f. You may assume that f is a positive function.