A manufacturer of precision digital switches has daily cost ????C and revenue ????R functions of ????(x)=10,000+8x dollars C(x)=10,000+8x dollars and ????(x)=10x−x22000 dollars, R(x)=10x−x22000 dollars, respectively, where xx is the daily production of switches. Production is increasing at a rate of 6060 switches per day when production is 10001000 switches. Find the rate of increase in cost when production is 10001000 switches per day. (Use decimal notation. Give your answer as a whole or exact number.)