maths functions




force of gravity, electrical attraction


	y = 1/d^2		(1/x^2)



exponential decay of tempreture, etc.


	y = 1/e^x		(1/e^x)




growth of shellfish,
	(increase in diameter)

	other examples	


	dy/dx = 1/x		


	constant deposition on a sphere of increasing size (check)


