P	Q	Arc elasticity	Point elasticity	TR	MR
7	100		14	700
6.5	200		13	1300	6
6	300		12	1800	5
5.5	400		11	2200	4
5	500		10	2500	3
4.5	600		9	2700	2
4	700		8	2800	1
3.5	800		7	2800	0
3	900		6	2700	-1
2.5	1000		5	2500	-2
2	1100		4	2200	-3
1.5	1200		3	1800	-4

Correct and show me how to get the point elasticity in steps