let be a function such that f(-1)=1 . at each point on the graph of , the slope is given by dy/dx=x^2-xy-y^2 . which of the following statements is true?
A. f has relative minimum at x=-1
B. f has relative maximum at x=-1
C. f has neither relative minimum nor relative maximum at x=-1
D. There is insufficient information to determine whether f
has a relative minimum, a relative maximum, or neither at x=−1