Tìm nghiệm của phương trình

Câu hỏi: Tìm nghiệm của phương trình $\sin 5\text{x}+{\text{cos}}^2\text{x}-{\sin }^2\text{x}=0$

A. $\left[\begin{array}{l}\text{x}=-\frac{\text{π}}{6}+\text{k}\frac{\text{π}}{3}\\ \text{x}=-\frac{\text{π}}{14}+\text{k}\frac{\text{π}}{7}\end{array}\right.$

B. $\left[\begin{array}{l}\text{x}=-\frac{\text{π}}{6}+\text{k}\frac{\text{2π}}{3}\\ \text{x}=-\frac{\text{π}}{14}+\text{k}\frac{\text{2π}}{7}\end{array}\right.$

C. $\left[\begin{array}{l}\text{x}=\frac{\text{π}}{6}+\text{k2π}\\ \text{x}=\frac{\text{π}}{14}+\text{k2π}\end{array}\right.$

D. $\left[\begin{array}{l}\text{x}=-\frac{\text{π}}{6}+\text{k2π}\\ \text{x}=-\frac{\text{π}}{14}+\text{k2π}\end{array}\right.$