Recent content by ross wils

this homework question has certainly confused me - thanks v much for that reply, but then it goes on to say that looking at that condition and this one, "sum of concave function theorem: if f(x) and g(x) are both concave (convex) functions, then f(x) + g(x) is also a concave (convex) function...

ive been staring at the problem for days, and that hasn't helped so far. i thought the left hand side of he inequality might be f[ax1 + (1-a)x2] ² + [ay1+ (1-a)y2] ² > with 1 variable the other condition is f(x) is strictly increasing in X iff for any two points in X, say x1, x2...

very urgent! consider the function, Z = x²+y² i need to say i) whether this is continuous ii) (strictly) increasing or decreasing i) then establish if the function is a concave, strictly concave, convex or strictly convex function using the typical definition f[aU + (1-a)V]...