Lượng giác lớp 10

R

rooney_cool

CM phương trình sau:
[TEX]\frac{1}{sin {10}^{o}}-\frac{\sqrt{3}}{cos {10}^{o}} = 4[/TEX]

[TEX]\frac{1}{sin {10}^{o}}-\frac{\sqrt{3}}{cos {10}^{o}} = 4[/TEX]

[TEX]\frac{1}{sin {10}^{o}}-\frac{\sqrt{3}}{cos {10}^{o}} = \frac{cos10^{o}-\sqrt{3}sin10^o}{sin10^0cos10^o}=4\frac{\frac{1}{2}cos10^o-\frac{\sqrt{3}}{2}sin10^o}{2sin10^ocos10^o}= 4 \frac{sin20^o}{sin^o} = 4[/TEX]
!!! :D
 
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