5. A rectangular garden measuring 800 m² is to be enclosed on two parallel sides by a stone wall that costs $35 per metre and the other two sides by wooden fencing that costs $20 per metre. What dimensions will minimize the total cost of enclosing the garden and what is the minimum cost (rounded to the nearest dollar)? 6. Use differentials to approximate each of the following. Give your answer as a fraction. [10 a. √82 b. √10001 dy 7. Find using implicit differentiation for the curve dx x22x3y²+5y+2=0. 8. Suppose that the number of traffic accidents in a region is modelled by N(p) = p²+2p+ 3000 where the population is p thousand. If the population is currently 40000 and is increasing at the rate of 3000 people per year, at what rate is the number of traffic accidents increasing?