Tìm nguyên hàm của hàm số \(f\left( x \right) = \frac{1}{{{{\sin }^2}2x}}.\)
A. \(\int {f\left( x \right)dx = 2\cot 2x + C.} \)
B. \(\int {f\left( x \right)dx = \frac{1}{2}\cot 2x + C.} \)
C. \(\int {f\left( x \right)dx = - 2\cot 2x + C.} \)
D. \(\int {f\left( x \right)dx = - \frac{1}{2}\cot 2x + C.} \)
A. \(\int {f\left( x \right)dx = 2\cot 2x + C.} \)
B. \(\int {f\left( x \right)dx = \frac{1}{2}\cot 2x + C.} \)
C. \(\int {f\left( x \right)dx = - 2\cot 2x + C.} \)
D. \(\int {f\left( x \right)dx = - \frac{1}{2}\cot 2x + C.} \)