Question

Номер 4 , помогите срочно:)

Answer 1

$\lim_{x \to 0} \frac{x*sin(3x)}{cosx-cos^3x}=\lim_{x \to 0} \frac{x*sin(3x)}{cosx(1-cos^2x)}=\\\\=\lim_{x \to 0} \frac{x*sin(3x)}{cosx*sin^2x}=\lim_{x \to 0} \frac{x*3x}{cosx*x^2}=\\\\=\lim_{x \to 0} \frac{3}{cosx}=3$