The first inequality means that the distance between x and c is greater than 0 and that x â  c, while the second indicates that x is within distance Î´ of c. Note that the above definition of a limit is true even if f(c) â  L. Indeed, the function f need not even be defined at c.
Once inside a hot water heater, however, Legionella bacteria multiplies and is conveyed through the household plumbing, where it may be inhaled in the aerosol mist that accompanies showering, bathing or even washing dishes in a sink. Very young children and elderly people are particularly at risk.
It takes one Btu per pound of water to raise the temperature by one degree Fahrenheit. The standard size of American hot water heaters is 40 gallons, and each gallon of water weighs 8.33 pounds. Calculate the Btu. If you have a 40-gallon water heater, that is 40 multiplied by 8.33, or 333.2 pounds of water. So you need 333.2 Btu to raise the water 1 degree Fahrenheit. However, most areas need more than one degree of heat added to the water to make it warm enough for showering or washing clothes or dishes.