x-1=t
х=t+1
если x → 1 ⇒ то t → 0
x^2-x=x*(x-1)=(t+1)*t
[m]=\lim_{t\to 0 }\frac{sint}{(t+1)t}=\lim_{t\to 0 }\frac{sint}{t}\cdot \frac{1}{t+1}=\lim_{t\to 0 }\frac{sint}{t}\cdot\lim_{t\to 0 }\frac{1}{t+1}=[/m]
[m]=1\cdot \frac{1}{0+1}=1[/m]