Question

Giai phương trình bậc nhất :

a/ \(2sinx+\sqrt{3}=0\)

b/ \(2cosx-\sqrt{3}=0\)

c/ \(2cosx-\sqrt{2}=0\)

d/ \(tanx+\sqrt{3}=0\)

Answer 1

a/ \(sinx=-\frac{\sqrt{3}}{2}=sin\left(-\frac{\pi}{3}\right)\Rightarrow\left[{}\begin{matrix}x=-\frac{\pi}{3}+k2\pi\\x=\frac{4\pi}{3}+k2\pi\end{matrix}\right.\)

b/ \(cosx=\frac{\sqrt{3}}{2}=cos\left(\frac{\pi}{6}\right)\Rightarrow x=\pm\frac{\pi}{6}+k2\pi\)

c/ \(cosx=\frac{\sqrt{2}}{2}=cos\left(\frac{\pi}{4}\right)\Rightarrow x=\pm\frac{\pi}{4}+k2\pi\)

d/ \(tanx=-\sqrt{3}=tan\left(-\frac{\pi}{3}\right)\Rightarrow x=-\frac{\pi}{3}+k\pi\)