Among the variations on the graphs of the trigonometric functions are shifts--both horizontal and vertical. Such shifts are easily accounted for in the formula of a given function. Take function f, where f (x) = sin(x) .
The running costs vary from gas to electric. The average running cost for an electric water heater is $550. The average running costs of a gas water heater is $400. The difference in usage price per year is $150.
I live in MA and the average water heater replacement install is about $100. It takes about 30 to 45 minutes. Maybe you are including the heater? Cost for a water heater here is 3 to $400. I personally have not had to pay for the replacement heater, as I buy one with a 5 to 7 year warranty, and they usually need replacing, just under my warranty time.