void latex()
{
   TCanvas *c1 = new TCanvas("c1", "test", 600, 700);
   // write formulas
   TLatex l;
   l.SetTextAlign(12);
   l.SetTextSize(0.04);
   l.DrawLatex(0.1, 0.9, "1)   C(x) = d #sqrt{#frac{2}{#lambdaD}}\
   #int^{x}_{0}cos(#frac{#pi}{2}t^{2})dt");
   l.DrawLatex(0.1, 0.7, "2)   C(x) = d #sqrt{#frac{2}{#lambdaD}}\
   #int^{x}cos(#frac{#pi}{2}t^{2})dt");
   l.DrawLatex(0.1, 0.5, "3)   R = |A|^{2} = #frac{1}{2}#left(#[]{#frac{1}{2}+\
   C(V)}^{2}+#[]{#frac{1}{2}+S(V)}^{2}#right)");
   l.DrawLatex(0.1, 0.3, "4)   F(t) = #sum_{i=-#infty}^{#infty}A(i)cos#[]{#frac{i}{t+i}}");
   l.DrawLatex(0.1, 0.1, "5)   {}_{3}^{7}Li");
   c1->Print("latex.ps");
}