√ 3sin 2x+cos 2x=2cosx-1
<=>2√3 sinx.cox+cos2x -sin2x -2cosx+cos2x+sin2x=0
<=>2√3sinx.cosx+2cos2x -2cosx=0
<=>cosx(√3sinx+cosx -1)=0
*cosx=0 =>x=pi/2+k.pi
*√3sinx+cosx -1=0
<=>sin(x+pi/6)=1/2 <=>x=...
a/\(\sin3x+\cos2x=1+2\sin x\cos2x\)
b/\(\sin^3x+\cos^3x=2\left(\sin^5x+\cos^5x\right)\)
c/\(\dfrac{\tan x}{\sin x}-\dfrac{\sin x}{\cos x}=\dfrac{\sqrt{2}}{2}\)
d/\(\dfrac{\cos x\left(\cos x+2\sin x\right)+3\sin x\left(\sin x+\sqrt{2}\right)}{\sin2x-1}=1\)
e/\(\sin^2x+\sin^23x-2\cos^22x=0\)
f/\(\dfrac{\tan x-\sin x}{\sin^3x}=\dfrac{1}{\cos x}\)
g/\(\sin2x\left(\cos x+\tan2x\right)=4\cos^2x\)
h/\(\sin^2x+\sin^23x=\cos^2x+\cos^23x\)
k/\(4\sin2x=\dfrac{\cos^2x-\sin^2x}{\cos^6x+\sin^6x}\)
mọi người giải giúp em với em đang cần gấp ạ
Giải PT
a1) \(3.\cos4x-2^{ }\cos^23x=1\)
a2) \(2\cos2x-8\cos x+7=\dfrac{1}{\cos x}\)
a3) \(\dfrac{\left(1+\sin x+\cos2x\right)\sin\left(x+\dfrac{\pi}{4}\right)}{1+\tan x}=\dfrac{1}{\sqrt{2}}\cos x\)
a4) \(9\sin x+6\cos x-3\sin2x+\cos2x=8\)
GIẢi các phương trình lượng giác
\(\left|\cos x\right|-\left|\sin x\right|-\cos2x\times\sqrt{1+\sin2x}\)
\(\sqrt{5\sin x+\cos2x}=-2\cos x\)
\(2\cos(x-45^0)-\cos(x-45^0)\times\sin2x-3\sin2x+4=0\)
\(\sin4x+2=\cos3x+4\sin x+\cos x\)
\(\cos^4x-\sin^4x=\left|\cos x\right|+\left|\sin x\right|\)
giải phương trình
\(\sin x\sqrt{1+2\sin x}=\cos2x\)
\(\sin\left(\frac{5x}{2}-\frac{\pi}{4}\right)-\cos\left(\frac{x}{2}-\frac{\pi}{4}\right)=\sqrt{2}\cos\frac{3x}{2}\)
\(3\sqrt{\tan x+1}\left(\sin x+2\cos x\right)=5\left(\sin x+3\cos x\right)\)
\(\sqrt{2}\left(\sin x+\sqrt{3}\cos x\right)=\sqrt{3}\cos2x-\sin2x\)
\(\sin2x\sin4x+2\left(3\sin x-4\sin^2x+1\right)=0\)
giải phương trình
1.\(sin^3x+2cosx-2+sin^2x=0\)
\(2.\frac{\sqrt{3}}{2}sin2x+\sqrt{2}cos^2x+\sqrt{6}cosx=0\)
3.\(2sin2x-cos2x=7sinx+2cosx-4\)
4.\(2cos2x-8cosx+7=\frac{1}{cosx}\)
5.\(cos^8x+sin^8x=2\left(cos^{10}x+sin^{10}x\right)+\frac{5}{4}cos2x\)
6.\(1+sinx+cos3x=cosx+sin2x+cos2x\)
7.\(1+sinx+cosx+sin2x+cos2x=0\)
Giai các pt sau
1. \(\sqrt{3}\cos5x-2\sin3x.\cos2x-\sin x=0\)
4. \(\sin3x+\cos3x-\sin x+\cos x=\sqrt{2}\cos2x\)
6. \(\sin x+\cos x.\sin2x+\sqrt{3}\cos3x=2\left(\cos4x+\sin x^3\right)\)
giải pt : \(\frac{\left(2\sin x-1\right)\left(\cos2x+\sin x+1\right)}{\sqrt{3}\sin x-\sin2x}=\sqrt{3}+2\cos x\)
Giải phương trình :
\(2+\sqrt{3}\left(\sin2x-3\sin x\right)=\cos2x+3\cos x\)
Giải các phương trình
a) \(\dfrac{\cos2x}{\sin2x-1}=0\)
b) \(\cos\left(\sin x\right)=1\)
c) \(2\sin^2x-1+\cos3x=0\)
d) \(tan3x.tanx=1\)
e) \(\cos3x=-\cos7x\)
