Công thức cộng lượng giác phần 1.

$\sin\left(\alpha+\beta\right)=\sin\alpha.\cos\beta+\sin\beta.\cos\alpha$

$\sin\left(\alpha+\beta\right)=\sin\alpha.\sin\beta+\cos\alpha.\cos\beta$

$\sin\left(\alpha+\beta\right)=\sin\alpha+\sin\beta$

$\cos\left(\alpha-\beta\right)=\cos\alpha.\cos\beta-\sin\alpha.\sin\beta$

 $\sin\left(x-y\right)=\sin y.\cos x-\sin x.\cos y$  

 $\cos\left(\alpha+\beta\right)=\cos\alpha.\cos\beta-\sin\alpha.\sin\beta$  

 $\tan\left(x+y\right)=\frac{\tan x+\tan y}{1-\tan x.\tan y}$  

 $1+\tan^2\theta=\frac{1}{1-\sin^2\theta}$  

 $\sin x>0$  

 $\cos x>0$  

 $\tan x>0$  

 $\cot x>0$  

 $\sqrt{2}\sin x+\sqrt{2}\cos x$  

 $\frac{1}{\sqrt{2}}\sin x+\frac{1}{\sqrt{2}}\cos x$  

 $\sin\left(\frac{5\pi}{4}-x\right)$  

 $\sin x-\cos x$  

 $\tan\left(\frac{\pi}{4}-\alpha\right)$  

 $\frac{1-\tan\alpha}{1+\tan\alpha}$  

 $\cot\left(\alpha+\frac{\pi}{4}\right)$  

 $\frac{1+\tan\alpha}{1-\tan\alpha}$  

 $\sin220\degree,\ \sin10\degree,\ \sin40\degree,\ \sin90\degree.$  

 $\sin40\degree,\ \sin90\degree,\ \sin220\degree,\ \sin10\degree.$  

 $\sin10\degree,\sin40\degree,\sin90\degree,\sin220\degree$  

 $\sin220\degree,\sin90\degree,\sin40\degree,\ \sin10\degree$  

$\sin x=\cos\left(x-\frac{\pi}{2}\right)$

$\sin\left(x-\pi\right)=\sin x$

$\tan\left(x-\pi\right)=\tan x$

$\cot\alpha=\cot\left(\alpha+\pi\right)$

6,3 cm.

6,4 cm.

7,5 cm.

5,8 cm.

 $-\frac{\sqrt{14}}{7}$  

 $\frac{\sqrt{14}}{3}$  

 $-\frac{14}{3}$  

 $\frac{\sqrt{14}}{7}$  

 $P=2$  

 $P=1$  

 $P=\frac{5}{3}$  

 $P=-1$