an industry consists of many identical firms each with cost function c(q)=q^2+1.when there are J active firms, each firm faces an identical inverse market demand p=10-15q-(J-1)q' whenever an identical output of q' is produced by each of the other (J-1) active firms.

Q:(a) with J active firms, and no possibility of entry or exit, what is the short-run equilibrium output q* of a representative firm act as Cournot competitors in choosing output?

(b) how many firms will be active in the long-run?

这里的成本函数“ c(q)=q^2+1”是有固定成本的，如何得到长期均衡啊？

请高人指教，谢谢！