\(\Leftrightarrow2sin\left(x+84^0\right).cos60^0=cos20^0\)
\(\Leftrightarrow sin\left(x+84^0\right)=cos20^0=sin70^0\)
\(\Rightarrow\left[{}\begin{matrix}x+84^0=70^0+k360^0\\x+84^0=110^0+k360^0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=-14^0+k360^0\\x=26^0+k360^0\end{matrix}\right.\)
Giúp mình giải gấp các pt bậc nhất theo sin x và cos x dạng a sin x +b cos x=c 1:sin(x+pi/6)+cos(x+pi/6)= căn6/2 2: ( căn 3-1) sinx-(căn3+1) cos x + căn 3-1=0 3: căn 3 sin 2x+sin(pi/2+2x)=1
\(\text{8 sin^2 x + 3 sin 2x + 3 sin x + cos x = 1.}\)
sin (2x + η/3 )= 5
Sin (2x+ η/10)= -2
Sin (x- η/6)= √3/2
Sin ( x-η/4)= √2/2
|2 sin x + cos x| + 3 sin x = 1.
|1 + sin x| + |1 + cos x| = sin x − cos x
giải các pt sau
1) \(\sqrt{2}\sin^3(x+\dfrac{\pi}{4})=2\sin x\)
2) \(\sin^3\left(x-\dfrac{\pi}{4}\right)=\sqrt{2}\sin x\)
\(\text{sin (\frac{\Pi}{6} + 3x) + sin (\frac{\Pi}{3} + x) + sin x = cos 5x.}\)
\(\text{√ sin x − √ cos x = 1 + √ sin x cos x;}\)
(3 sin x + 4 cos x)2 = 25 + |5 sin x − 3|
Giải các pt lượng giác sau
1) \(cos^2\left(x-\frac{\pi}{6}\right)-sin^2\left(x-\frac{\pi}{6}\right)=sin\left(x+\frac{\pi}{3}\right)\)
2) \(sin^4-sin^4\left(x+\frac{\pi}{2}\right)=sin\left(x+\frac{\pi}{3}\right)\)
3) \(8cos^3\left(x-\frac{\pi}{3}\right)-1=0\)