일간 보관물: 2011/12/24

최대공약수

완전미방 (1+xycos y + x sin y) y’ + ysin y = Ax^2

무리함수 적분- 삼각함수치환

완전미방  (x+y)^2 dx + (2xy+x^2 -1)dy = 0  

Proof of Kepler’s first law from Newtonian dynamics A planet orbits the Sun in an ellipse, with the Sun at one focus of the ellipse. http://radio.astro.gla.ac.uk/a1dynamics/ellproof.pdf ellproof