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Câu hỏi: Tích phân $\int\limits_{0}^{\dfrac{\pi }{2}}{\sin x \text{d}x}$ bằng
A. $-1$.
B. $2$.
C. $1$.
D. $0$.
A. $-1$.
B. $2$.
C. $1$.
D. $0$.
$\int\limits_{0}^{\dfrac{\pi }{2}}{\sin x \text{d}x}$ $=\left( -\cos x \right)\left| \begin{matrix}
\dfrac{\pi }{2} \\
0 \\
\end{matrix} \right.$$=-\cos \dfrac{\pi }{2}+\cos 0=1$.
\dfrac{\pi }{2} \\
0 \\
\end{matrix} \right.$$=-\cos \dfrac{\pi }{2}+\cos 0=1$.
Đáp án C.