Hello, I need help with these grade 12 calculus and vector math questions, please. For a good review please be detailed and thorough when answering the questions. And please answer all the questions correctly too :)

1. Find two positive integers with a sum of 20 and whose product is a maximum. 2. A rectangular pen is to be built with 1200 m of fencing. The pen is to be divided into three parts using two parallel partitions. Find the maximum possible area of the pen. 3. A cylindrical can is to have a volume of IL. Find the height and radius of the can that will minimize the surface area. Recall, 1mL = 1 cm3. 4. Use implicit differentiation to find ::for each of the following: a)x3+y3=9 b)2x2+y2=36 c) x3+x2y+4y3=6 5. Determine an equation of the tangent to the curve at the given point. a) x2 + 9312 = 37, (1, 2) b) y4 + x2y3 = 5, (2, 1)