Помогите,пожалуйста) №59,61,63,65,56,58

[latex]56)\; \; \lim\limits _{x \to \infty} (\sqrt{x^2+4x}-x)= \lim\limits _{x \to \infty} \frac{(\sqrt{x^2+4x}-x)(\sqrt{x^2+4x}+x)}{x(\sqrt{x^2+4x}+x)} =\\\\= \lim\limits _{x \to \infty} \frac{x^2+4x-x^2}{x(\sqrt{x^2+4x}+x)} =\lim\limits _{x\to \infty }\frac{4}{\sqrt{x^2+4x}+x}=[\, \frac{4}{\infty }\, ]=0\\\\58)\; \; \lim\limits _{x \to \infty} \frac{\sqrt{x^2+1}}{x+1} =\lim\limits _{x\to \infty }\frac{\sqrt{1+\frac{1}{x^2}}}{1+\frac{1}{x}}=\frac{\sqrt{1+0}}{1+0}=1\\\\59)\; \; \lim\limits _{x\to 0}\frac{sin7x}{x}=\lim\limits_{x \to 0}(\frac{sin7x}{7x}\cdot 7)=7[/latex] [latex]61)\; \; \lim\limits _{x\to 0}\frac{sin2x^2}{2x^2}=1\\\\63)\; \; \lim\limits _{x\to 0}\frac{sin^2x}{x^2}=\lim\limits _{x\to 0}\frac{sinx\cdot sinx}{x\cdot x}=1\\\\65)\; \; \lim\limits _{x\to 0}\frac{sin3x}{sin4x}=\lim\limits _{x\to 0}\frac{3x}{4x}=\frac{3}{4}[/latex]