

CMR: a/ [tex]\frac{1}{sin\frac{\pi }{10}}-\frac{1}{sin\frac{3\pi }{10}}=2[/tex]
b/ [tex]\frac{1}{sin10^{\circ}}-\frac{\sqrt{3}}{cos10^{\circ}}=4[/tex]
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b/ [tex]\frac{1}{sin10^{\circ}}-\frac{\sqrt{3}}{cos10^{\circ}}=4[/tex]
Mình cảm ơn ạ