\[\mathop {{\mathop{\rm li}\nolimits} \mathop {\lim }\limits_{x \to 0} \frac{{{3^{{x^2}}} - \cos x}}{{{x^2}}}}\limits_{} \]
công thức:
[laTEX]\lim_{ u \to 0 } \frac{a^u -1}{u} = lna \\ \\ \lim_{ u \to 0 } \frac{sinu}{u} = 1 \\ \\ L = \lim_{ x \to 0 } \frac{3^{x^2} -1}{x^2} + \lim_{ x \to 0 } \frac{1-cosx}{x^2} \\ \\ L= ln3 + \lim_{ x \to 0 } \frac{2sin^2(\frac{x}{2})}{x^2} \\ \\ L = ln3 + \lim_{ x \to 0 } \frac{sin(\frac{x}{2}).sin(\frac{x}{2})}{2.\frac{x}{2}.\frac{x}{2}} \\ \\ L = ln3 + \frac{1}{2}[/laTEX]