Area of a circle trigonometry, uses the coarea formula. Define a function formula_10 by formula_11. Note ρ is a Lipschitz function whose gradient is a unit vector formula_12 (almost everywhere). Let "D" be the disc formula_13 in formula_14. We will show that formula_15, where formula_16 is the two-dimensional Lebesgue measure in formula_14. We shall assume that the one-dimensional Hausdorff measure of the circle formula_18 is formula_19, the circumference of the circle of radius "r". (This can be taken as the definition of circumference.) Then, by the coarea formula, Similar to the onion proof outlined above, we could exploit calculus in a different way in
What Goes Around Comes Around What Goes Around Comes Around What Goes Around Comes Around is an album by Waylon Jennings, released on RCA Victor in 1979. By 1979, Jennings was on the tail end a hot streak that had made him one of the biggest superstars in country music. He had scored twelve Top 10 country hits since 1973 (including six chart toppers) and had recorded 4 straight #1 country albums, with 1977's "Ol' Waylon" also hitting #15 on the pop charts. Along with fellow outlaw Willie Nelson, he was at the forefront of what was being referred to as outlaw country, a musical