Giai giùm đề toán này cái !!!!

N

niemkieuloveahbu

[TEX]f(x)=\frac{sin3x}{3}+cosx-\sqrt{3}(sinx+\frac{cos3x}{3})\\ \Rightarrow f'(x)=cos3x-sinx-\sqrt{3}cosx+\sqrt{3}sin3x\\ f'(x)=0\\ \Leftrightarrow cos3x+\sqrt{3}sin3x=sinx+\sqrt{3}cosx\\ \Leftrightarrow cos(3x-\frac{\pi}{3})=cos(x-\frac{\pi}{6})[/TEX]

PT cơ bản,:)

[TEX]f''(x)=-3sin3x-cosx+\sqrt{3}sinx+3\sqrt{3}cos3x\\ \Rightarrow f''(0)=-1+3\sqrt{3}[/TEX]
 
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