3. The graph of L'(w) shows the rate at which a human fetus' growth (length) changes. Use the graph and its provided grid to find the length change of a fetus between 20 weeks and 40 weeks! (hint: you need to set up a definite integral and use that as part of your work). (8 points) length growth rate (cm/week) 1 L'(w) 8 16 24 32 22 age of fetus (weeks after menstration)