Question 3.3 (8 marks) It turns out that your friends have allergies to chicken and now they're into moto-cross. They have a small square backyard which is 4m long and 4m wide. They want to create a hill area so that they can have motocross fun in the backyard. More precisely, they want that there are four nicely spaced-out hills! You remember your MAT9004 lectures and the following functions comes to your mind (of course!): f($, y) = 1051;23:26'52392 + 20. Explain to your friend how the plot of this function could help them to model their backyard! Specically, do the following: determine all stationary points of f (11:, y) and classify those for which the Hessian test is not inconclusive; explain what this has to do with your friend's design for the backyard. Note: For the classification of stationary points, you are not required to compute the Hessian matrix by hand, but you can simply use WoljcrantAlpha to compute the required determinant values; you need to write down these values and explain what they tell you! n-_.....l.=.... '1 A f( \"'41-...'u