Description: Properties studied of a function describing stock market crash functions of financial bubbles: periodicity, availability of asymptotes and zeroes. Trigonometric properties of logoperiodical component of this function are discussed. Expressions were obtained for double angle cosine, sum cosine and cosine of difference between trigonometric functions and logoperiodical argument. A differential equation is shown whose solution leads to logoperiodical function.
Keywords: stock market crash, financial bubble, financial bubble functions, logoperiodical function, trigonometry of logoperiodical argument functions, differential equations