{ "id": "1601.01841", "version": "v1", "published": "2016-01-08T12:02:22.000Z", "updated": "2016-01-08T12:02:22.000Z", "title": "Expected number of real roots of random trigonometric polynomials", "authors": [ "Hendrik Flasche" ], "comment": "15 pages", "categories": [ "math.PR" ], "abstract": "We investigate the asymptotics of the expected number of real roots of random trigonometric polynomials $$ X_n(t)=u+\\frac{1}{\\sqrt{n}}\\sum_{k=1}^n (A_k\\cos(kt)+B_k\\sin(kt)), \\quad t\\in [0,2\\pi],\\quad u\\in\\mathbb{R} $$ whose coefficients $A_k, B_k$, $k\\in\\mathbb{N}$, are independent identically distributed random variables with zero mean and unit variance. If $N_n[a, b]$ denotes the number of real roots of $X_n$ in an interval $[a,b]\\subseteq [0,2\\pi]$, we prove that $$ \\lim_{n\\rightarrow\\infty} \\frac{\\mathbb{E} N_n[a,b]}{n}=\\frac{b-a}{\\pi\\sqrt{3}} e^{-\\frac{u^2}{2}}. $$", "revisions": [ { "version": "v1", "updated": "2016-01-08T12:02:22.000Z" } ], "analyses": { "subjects": [ "26C10", "30C15", "42A05", "60F99", "60G15" ], "keywords": [ "random trigonometric polynomials", "real roots", "expected number", "independent identically distributed random variables", "zero mean" ], "note": { "typesetting": "TeX", "pages": 15, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2016arXiv160101841F" } } }