Google
Câu hỏi: Tích phân $\int_0^1 \dfrac{1}{\sqrt{x+1}} \mathrm{~d} x$ bằng
A. $2(\sqrt{2}-1)$.
B. $\ln 2$.
C. $\dfrac{\sqrt{2}-1}{2}$.
D. $\sqrt{2}-1$.
A. $2(\sqrt{2}-1)$.
B. $\ln 2$.
C. $\dfrac{\sqrt{2}-1}{2}$.
D. $\sqrt{2}-1$.
Ta có $\int_0^1 \dfrac{1}{\sqrt{x+1}} \mathrm{~d} x=2 \int_0^1 \dfrac{1}{2 \sqrt{x+1}} \mathrm{~d}(x+1)=\left.2 \sqrt{x+1}\right|_0 ^1=2(\sqrt{2}-1)$.
Đáp án A.