A.\(\dfrac{{172\pi {a^2}}}{3}\).
B.\(\dfrac{{76\pi {a^2}}}{3}\).
C.\(84\pi {a^2}\).
D.\(\dfrac{{172\pi {a^2}}}{9}\)

A.Năm \(2028\).
B.Năm \(2047\).
C.Năm \(2027\).
D.Năm \(2046\).

A.\(\left[ {4\,;\,7} \right)\).
B.\(\left( {4\,;\,7} \right]\).
C.\(\left( {4\,;\,7} \right)\).
D.\(\left( {4\,;\, + \infty } \right)\).

A.\(\dfrac{{{x^2} + 2x - 2}}{{2\sqrt {{x^2} + 2} }} + C\).
B.\(\dfrac{{x - 2}}{{\sqrt {{x^2} + 2} }} + C\).
C.\(\dfrac{{2{x^2} + x + 2}}{{\sqrt {{x^2} + 2} }} + C\).
D.\(\dfrac{{x + 2}}{{2\sqrt {{x^2} + 2} }} + C\).

A.\(3\).
B.\(6\).
C.\(12\).
D.\(2\).

A.\(5\sqrt 2 \).     
B.\(\sqrt {26} \).
C.\(26\).
D.\(50\).

A.\(32\sqrt 2 \).
B.\( - 40\).
C.\( - 32\sqrt 2 \).
D.\( - 45\).

A.\(8\pi \).
B.\(\dfrac{{16\sqrt 3 \pi }}{3}\).
C.\(\dfrac{{8\sqrt 3 \pi }}{3}\).
D.\(16\pi \).

A.\(\left( {4\,;\, + \infty } \right)\).
B.\(\left( { - 4\,;\,4} \right)\).
C.\(\left( { - \infty \,;\,4} \right)\).
D.\(\left( {0\,;\,4} \right)\).

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