For example, (x +1)*(x +1) is a term built from the constant 1, the variable x, and the binary function symbols + and *; it is part of the atomic formula (x +1)*(x +1) â¥ 0 which evaluates to true for each real-numbered value of x.
In recent weeks, the U.S. diesel fuel price has been hovering around $4.16 per gallon. LNG is selling for about $2.92 per diesel gallon equivalent, 30 percent less, according to Clean Energy Fuels' current price report, which is updated weekly.
Between 1999 and 2008, the national annual average residential natural gas price more than doubled, from $6.69 per thousand cubic feet (Mcf) to $13.68 per Mcf. The national average price of natural gas is only part of the story, as the prices in individual States can differ greatly.