\(cos\left(2x+1\right)=cos\left(2x-1\right)\)
\(\Leftrightarrow cos\left(2x+1\right)-cos\left(2x-1\right)=0\)
\(\Leftrightarrow-2sin2x.sinx\left(2\right)=0\)
\(\Leftrightarrow sin2x=0\)
\(\Leftrightarrow2x=k\pi\)
\(\Leftrightarrow x=\dfrac{k\pi}{2}\)
1. Tìm m để PT có nghiệm:
a) \(\sqrt{3}\cos^2x+\dfrac{1}{2}\sin2x=m\)
b) \(3\sin^2x-2\sin x\cos x+m=0\)
c) \(\sin^2x+2\left(m-1\right)\sin x\cos x-\left(m+1\right)\cos^2x=m\)
1. Tìm m để PT có nghiệm:
a) \(\sqrt{3}\cos^2x+\dfrac{1}{2}\sin2x=m\)
b) \(3\sin^2x-2\sin x\cos x+m=0\)
c) \(^{ }\sin^2x+2\left(m-1\right)\sin x\cos x-\left(m+1\right)\cos^2x=m\)
Giải pt sau:
cos(2x+1)=cos(2x-1)
a) cos^6x+sin^2x=1
b)cos^6x-sin^6x=13/18cos^2(2x)
c)cos^4x+sin^6x=cos2x
d)2cos^2(2x)+cos2x=4sin^2(2x) cos^2x
sinx + cos x+ 1+ sin 2x+ cos 2x =0
Tìm TXĐ:
a, \(y=\dfrac{1}{2}\sin\left(2x-1\right)-\cos\left(x^2-2\right)\).
b, \(y=\sin\sqrt{2x-4}\).
c, \(y=\sqrt{1-\cos^2x}\).
Sin 2x - cos 2x +3 sin x - cos x - 1 = 0
cos(2x+\(\dfrac{\pi}{4}\))+cos(2x-\(\dfrac{\pi}{4}\))+4sinx=2+\(\sqrt{2}\)(1-sinx)
Giải phương trình
\(\left(sin^2x-\frac{1}{sin^2x}\right)^2+\left(cos^2x-\frac{1}{cos^2x}\right)^2=\frac{7}{2}-sin^2y+2siny\)
