Find local minima for the following problems (hint: find max( - ƒ (x,y))) • (a) f(x,y)=16(8x3 +3x²-3x+6xy+3y+3y²) (x,y) = (________) => min[f(x,y)]= (b) f(x,y)=16(8x³+3x² -3x+6xy+3y+3y²) subject to x+y= ½ (x,y) = (__________ ) => min[f(x,y)] = (c) f(x,y)=16(8x³ +3x² -3x+6xy+3y+3y²) subject to x+y≤½, x≥0, y≥0 (x,y) = () => min [f(x,y)]= [2 1 1] (d) Find an inverse matrix of 1 2 1: [1 1 2] SHOW your work on the following pages.