Find the critical points of the function
��=�
4
−8�
2
.
A B
C D
−2,−16,0,0,(2,−16)
−2,−16,0,0,(4,128)
−4,128,0,0,(2,−16)
−4,128,0,0,(4,128)
�
′
�=0
⇒4�
3
−16�=0
⇒4��
2
−4=0
⇒4��−2(�+2)=0
⇒�=0,2,−2
�−2=−16
�0=0
�2=−16
So, critical points are:
−2,−16,0,0,(2,−16)