2. 6.45 Charles owns a home with solar panels on the roof. His utility company has a “buy-back” program that charges homeowners for the net energy used each quarter. He listed the quarterly charges and buy-back dollars for the 2 years he has been in the program.

(a) Use Descartes’

rule to determine the maximum number of possible i* values.

(b) Use Norstrom’s criterion to determine if there is only one positive i* value.

(c) Determine the i* value(s) for Charles.

Table Summary: Table divided into 3 columns with the headings marked as: Quarter; Charges in dollars; and Buy-back in dollars.

Quarter Charges, $ Buy-back, $

1 −200 50 2 −100 100 3 −100 250 4 −100 260 5 −100 200 6 −150 170 7 −120 150 8 −150 20