Solving problems with exponential growth The graph shows how bacteria (y) grows over time (t). The equation of the graph is: y = 20 g t From the graph, when t = 2 y = 2, 000.

Example Part of the graph of y = 2 x 2 is shown below. Find the gradient of the curve at the point where x = 2. Solution Draw a tangent to the curve at the point where x = 2.