Question

решить lim x->0 (sin7x+sin3x)/x*sinx

Answer 1

$lim_{xto0}frac{sin7x+sin3x}{xsinx}=[sin7x approx 7x; sin3x approx 3x; sinx approx x]= \ \ =lim_{xto0}frac{7x+3x}{x*x}=lim_{xto0}frac{10x}{x^2}=lim_{xto0}frac{10}{x}=frac{10}{0}=infty$