Một nguyên hàm của hàm số: $y = \frac{1}{{{{\sin }^2}x + 2{{\cos }^2}x}}$ là

A. $I = \frac{{4({x^2} + 5)}}{{7\sqrt[4]{x}}} + C$

B. $I = \frac{{3({x^2} + 7)}}{{7\sqrt[3]{x}}} + C$

C. $I = \frac{{3({x^2} + 7)}}{{7\sqrt[4]{x}}} + C$

D. $I = \frac{{4({x^2} + 7)}}{{7\sqrt[4]{x}}} + C$

A. $A = \left( {\begin{array}{*{20}{c}}\begin{array}{l}1\\ - 2\\ - 1\end{array}&\begin{array}{l} - 2\\0\\0\end{array}&\begin{array}{l} - 1\\0\\0\end{array}\end{array}} \right)$

B. $A = \left( {\begin{array}{*{20}{c}}\begin{array}{l}1\\ - 1\\\frac{{ - 1}}{2}\end{array}&\begin{array}{l} - 1\\0\\0\end{array}&\begin{array}{l}\frac{{ - 1}}{2}\\0\\0\end{array}\end{array}} \right)$

C. $A = \left( {\begin{array}{*{20}{c}}\begin{array}{l}\frac{1}{2}\\ - 1\\\frac{{ - 1}}{2}\end{array}&\begin{array}{l} - 1\\0\\0\end{array}&\begin{array}{l}\frac{{ - 1}}{2}\\0\\0\end{array}\end{array}} \right)$

A. $- \cot \frac{x}{2}$

B. $\cot \frac{x}{2}$

C. $- \frac{1}{2}\cot g\frac{x}{2}$

D. $- 2\cot g\frac{x}{2}$

A. m > 2

B. m≤2

C. m = 2

D. ∀m∈R

A. $I = \frac{1}{2}{e^{2x}} - {e^x} + x + C$

B. $I = \frac{1}{2}{e^{2x}} - {e^{ - x}} + x + C$

C. $I = \frac{1}{2}{e^{3x}} - {e^{ - x}} + x + C$

D. $I = \frac{1}{2}{e^{2x}} + {e^{ - x}} + x + C$

A. m > 25

B. m≤25

C. m = 25

D. Không có giá trị m

A. 1

B. 2

C. -2

D. -3