Does an increase in average income cause a shift of the demand curve for coffee or a movement along the demand curve? Explain briefly.

1.2 Given the estimated demand function, Equation 2.2, for coffee, Q = 8.56 - p - 0.3ps + 0.1Y, use algebra (or calculus) to show how the demand curve shifts as per capita income, Y, increases by $10,000 a year. Illustrate this shift in a diagram.

1.3 Using the coffee demand function, Q = 8.56 - p - 0.3ps + 0.1Y, show that sugar is a complement for coffee. You can use a numerical example, algebra, or calculus