\(\Leftrightarrow2\cos^3x+2\cos^2x-1+\left(1-\cos^2x\right)=0\)
\(\Leftrightarrow2\cos^3x+\cos^2x=0\)
\(\Leftrightarrow\left[{}\begin{matrix}\cos x=\dfrac{-1}{2}\\\cos=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2\sqcap}{3}+k2\sqcap\\x=\dfrac{-2\sqcap}{3}+k2\sqcap\\x=\dfrac{\sqcap}{2}+k\sqcap\end{matrix}\right.\)
Giải các phương trình sau :
a) \(\sin\left(x-\frac{2\pi}{3}\right)=\cos2x\)
b) \(\frac{\sin^3x+\cos^3x}{2\cos x-\sin x}=\cos2x\)
1) sin3x+sin2x+sinx=cos2x+cosx+1
2) cos2x + cos23x = sin22x
giải phương trình: \(\sin2x+3\cos2x+8\sin x+14\cos x+11=0\)
\(sinx+4cosx=2+sin2x\)
\(\left(1-sin2x\right)\left(sinx+cosx\right)=cos2x\)
\(1+sinx+cosx+sin2x+cos2x=0\)
\(sinx+sin2x+sin3x=1+cosx+cos2x\)
\(sin^22x-cos^28x=sin\left(\dfrac{17\pi}{2}+10x\right)\)
giải các pt
a) \(1-2cos2x-\sqrt{3}sinx+cosx=0\)
b) \(cos2x+cos^2x-sinx.cosx=8\left(cosx-sinx\right)\)
c) \(sin^2x+3sinx.cosx-4cos^2x=4\left(sinx-cosx\right)\)
d) \(\frac{cos^3x-sin^3x}{2cosx+3sinx}=cos2x\)
a)\(\dfrac{2sin^2\left(\dfrac{3x}{2}-\dfrac{\pi}{4}\right)+\sqrt{3}cos^3x\left(1-3tan^2x\right)}{2sinx-1}=-1\)
b)\(\dfrac{2sin2x-cos2x-7sinx+4+\sqrt{3}}{2cosx+\sqrt{3}}=1\)
c)\(\dfrac{\left(1+sinx+cos2x\right)sin\left(x+\dfrac{\pi}{4}\right)}{1+tanx}=\dfrac{1}{\sqrt{2}}cosx\)
d)\(\left(\sqrt{3}sin2x+1\right)\left(2sinx-1\right)+sin3x-cos2x-sinx=0\)
\(1,sin^{2008}x+cos^{2008}x=1\)
\(2,sin^5x+cos^5x+sin2x+cos2x=1+\sqrt{2}\)
\(3,4cos^2x+3tan^2x-4\sqrt{3}cosx+2\sqrt{3}tanx+4=0\)
giải phương trình: \(\dfrac{5\left(\sqrt{3}\sin x+\cos x\right)-\sqrt{3}\cos2x+\sin2x-6}{\cot x-1}=0\)
Giải các phương trình sau:
1) sin2x + sin23x - 3cos22x = 0
2) sin22x + sin24x = sin26x
3) cos4x - 5sin4x = 1
4) sin24x + sin23x = cos22x +cos2x với x∈(0;π)
5) 4sin3x - 1 = 3 - √3cos3x
6)sin2x = cos22x + cos23x
