Questions in fun-lim

Select	Question
	$\underset{x\to 0}{\mathop{\lim }}\,\frac{{{y}^{2}}}{x}=........$ , where ${{y}^{2}}=ax+b{{x}^{2}}+c{{x}^{3}}$
	$\underset{x\to 0}{\mathop{\lim }}\,\frac{{{(1+x)}^{1/2}}-{{(1-x)}^{1/2}}}{x}=$
	$\underset{x\to 1}{\mathop{\lim }}\,\frac{{{x}^{3}}-1}{{{x}^{2}}+5x-6}=$
	$\underset{x\to a}{\mathop{\lim }}\,\frac{\sqrt{a+2x}-\sqrt{3x}}{\sqrt{3a+x}-2\sqrt{x}}=$
	$\underset{x\to 1}{\mathop{\lim }}\,\frac{1-{{x}^{-1/3}}}{1-{{x}^{-2/3}}}=$
	$\underset{x\to 0}{\mathop{\lim }}\,\frac{{{(1+x)}^{n}}-1}{x}=$
	$\underset{x\to 0}{\mathop{\lim }}\,\left( \frac{\tan 3x}{x}+\cos x \right)=$
	$\underset{x\to 0}{\mathop{\lim }}\,\frac{\sqrt{1+x}-\sqrt{1-x}}{{{\sin }^{-1}}x}=$
	$\underset{y\to 0}{\mathop{\lim }}\,\frac{(x+y)\sec (x+y)-x\sec x}{y}=$
	$\underset{x\to 0}{\mathop{\lim }}\,\frac{x{{.2}^{x}}-x}{1-\cos x}=$