A.\(\dfrac{\pi }{4}\)
B.\(\dfrac{\pi }{2}\)
C.\(\dfrac{{{\pi ^2}}}{4}\)
D.\(\dfrac{{{\pi ^2}}}{2}\)

A.\(6\)
B.\(5\)
C.\(8\)
D.\(7\)

A.\( - 16\)
B.\(28\)
C.\(16\)
D.\( - 28\)

A.\(4\)
B.\(2\)
C.\(1\)
D.\(3\)

A.\(\dfrac{{\sqrt {14} a}}{3}\)
B.\(\dfrac{{\sqrt {14} a}}{6}\)
C.\(\sqrt {14} a\)
D.\(\dfrac{{\sqrt {14} a}}{{12}}\)

A.\( - 26\)
B.\(26\)
C.\( - 34\)
D.\(34\)

A.\(4\,687\,000\) đồng.
B.\(4\,697\,000\) đồng.
C.\(4\,690\,000\) đồng
D.\(4\,700\,000\) đồng.

A.\(6 + \sqrt {37} \)
B.\(5 + \sqrt {23} \)
C.\(6 + \sqrt {11} \)
D.\(6 + \sqrt {13} \)

A.\(10\)
B.\(26\)
C.\(1\)
D.\(53\)

A.\(\left( {3;1; - 2} \right)\)
B.\(\left( {\dfrac{1}{2}; - \dfrac{3}{2};2} \right)\)
C.\(\left( { - \dfrac{1}{2};\dfrac{3}{2}; - 2} \right)\)
D.\(\left( {\dfrac{3}{2};\dfrac{1}{2}; - 1} \right)\)