Consider the f(x, y) = x2 + y2 ‚Äö√Ñ√∂‚àö√ë‚àö¬® a. For what values of a do we have critical points for the function

for any real number except zero

a ‚Äö√Ñ√∂‚àö‚Ä†‚àö¬ß (0, +‚Äö√Ñ√∂‚àö‚Ä†‚àö¬™)

a ‚Äö√Ñ√∂‚àö‚Ä†‚àö¬ß (-1, 1)

Consider the f(x, y) = x2 + y2 ‚Äö√Ñ√∂‚àö√ë‚àö¬

1.	Consider the f(x, y) = x² + y² ‚Äö√Ñ√∂‚àö√ë‚àö¬® a. For what values of a do we have critical points for the function
A.	independent of a
B.	for any real number except zero
C.	a ‚Äö√Ñ√∂‚àö‚Ä†‚àö¬ß (0, +‚Äö√Ñ√∂‚àö‚Ä†‚àö¬™)
D.	a ‚Äö√Ñ√∂‚àö‚Ä†‚àö¬ß (-1, 1)
Answer» B. for any real number except zero