1. Approximate [ (x2 +5) dx by computing the area of each rectangle and adding. YA 20- 15- 10- 5 2. A company determines that the marginal cost, in dollars, of the xth gadget that it manufactures is given by: C'(x) =-0.003x + 50, with C(0) = $0. Find the total cost of producing 200 gadgets. 3. Give an interpretation of the shaded area under the curve shown below. of gallons per hour) Rate of water use (in hundreds Time (in hours) 4. Find the derivative of the following function g(t) = t/ (t + 1) using the difference quotient method. 5. If y = f(u), u = g(v) and v = h(x), how to obtain dy/dx? 6. Let y = x'(4-x)05. What is dy/dx