1.1. A spin-off company from UNISA enterprises that produces an environmentally friendly lixiviant for leaching refractory gold ores has determined that the price and the monthly demand of its lixiviant are related by the expression D2=40002p, where p is the price per tonne in rands and D is the monthly demand in tonnes. The associated fixed costs are R11250.00 per month, and the variable costs are R1000. 00/ tonne. i) Show that the first derivative of the total profit (Pr) per month is given by the following expression: dDdPr=D2+1000 (Show all step and reasoning) ii) What is the optimal number of units that should be produced and sold each month? [3] iii) Develop an expression/ equation that can be used to determine the value of D at the breakeven point? [2] 1.1. A spin-off company from UNISA enterprises that produces an environmentally friendly lixiviant for leaching refractory gold ores has determined that the price and the monthly demand of its lixiviant are related by the expression D2=40002p, where p is the price per tonne in rands and D is the monthly demand in tonnes. The associated fixed costs are R11250.00 per month, and the variable costs are R1000. 00/ tonne. i) Show that the first derivative of the total profit (Pr) per month is given by the following expression: dDdPr=D2+1000 (Show all step and reasoning) ii) What is the optimal number of units that should be produced and sold each month? [3] iii) Develop an expression/ equation that can be used to determine the value of D at the breakeven point? [2]