Exercício Resolvido de Limites
b)
\( \displaystyle \lim_{x\rightarrow \frac{\pi }{2}}\;\left(2\operatorname{sen}x-\cos x+\operatorname{cotg}x\right) \)
A cotangente é dada por
\[ \bbox[#99CCFF,10px]
{\operatorname{cotg}x=\frac{\cos x}{\operatorname{sen}x}}
\]
\[
\lim_{x\rightarrow \frac{\pi}{2}}\;\left(2\operatorname{sen}x-\cos x+\frac{\cos x}{\operatorname{sen}x}\right)
\]
Substituindo diretamente o valor
\[
\begin{gathered}
\lim_{x\rightarrow \frac{\pi}{2}}\;\left(2\operatorname{sen}\frac{\pi}{2}-\cos \frac{\pi}{2}+\frac{\cos \frac{\pi}{2}}{\operatorname{sen}\frac{\pi}{2}}\right)\\[5pt]
\lim_{x\rightarrow \frac{\pi}{2}}\;\left(2.1-0+\frac{0}{1}\right)
\end{gathered}
\]
\[ \bbox[#FFCCCC,10px]
{\lim_{x\rightarrow \frac{\pi}{2}}\;\left(2\operatorname{sen}x-\cos x+\operatorname{cotg}x\right)=2}
\]