b"\n_START_ARTICLE_\nVariacija (matematika)\n_START_SECTION_\nPavyzdys\n_START_PARAGRAPH_\nFunkcija_NEWLINE_F(x)=\\int\\limits_{a}^{b} f(t,x,x')dx_NEWLINE_jos variacija_NEWLINE_\\delta F(x)=\\frac{d}{d\\alpha}\\int\\limits_{a}^{b}f\\Big(t,x(t)+\\alpha h(t), x'(t)+\\alpha h'(t)\\Big)dt\\Bigg|_{\\alpha =0}=\\int\\limits_{a}^{b}\\Big[f_x'\\Big(t,x(t),x'(t)\\Big)h(t)+f_{x'}'\\Big(t,x(t),x'(t)\\Big)h'(t)\\Big]dt"