:D tich phan

N

nguyenbahiep1

[laTEX]I = \int_{0}^{\pi}x.sinx.cos^2xdx \\ \\ u = x \Rightarrow du = dx \\ \\ dv = sinx.cos^2xdx \Rightarrow v = - \frac{cos^3x}{3} \\ \\ I = - x\frac{cos^3x}{3} \big|_0^{\pi} + \int_{0}^{\pi} \frac{cos^3x}{3}dx[/laTEX]

đến đây hạ bậc cos là xong

[laTEX]cos^3x = \frac{cos3x+3cosx}{4}[/laTEX]
 
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