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.
Cost to heat water a 40-gallon tank with gas The federal standard for gas water heaters is only 55.6-59.4% efficiency (higher for smaller tanks), and actual models are rarely much better, except for Energy Star models which are at least 67% efficient. (DoE 2010, p. 9) Gas price figured at $1.42/therm.