UV আকারের (Integration by parts)

f(x)=sinx+cosx, g(x)=lnx 

  x2{g(x)}2dx \int x^{2} \left \lbrace g{\left ( x \right )} \right \rbrace^{2} dx   এর মান নিচের কোনটি ?  

x2(lnx)2dx=(lnx)2x2dx{ddx(lnx)2x2dx}dx=x3(lnx)2323lnx2dx \begin{aligned} & \int x^{2}(\ln x)^{2} d x=(\ln x)^{2} \int x^{2} d x-\int\left\{\frac{d}{d x}(\ln x)^{2} \int x^{2} \cdot d x\right\} d x \\ = & \frac{x^{3}(\ln x)^{2}}{3}-\frac{2}{3} \int \ln x^{2} d x \end{aligned}

=x3(lnx)2323lnxx2dx=x3(lnx)2323[lnxx2dx{ddx(lnx)x2dx]dx]=x3(lnx)232/3[x3lnx313x2dx]=x3(lnx)2329x3lnx2913x3 \begin{array}{l} =\frac{x^{3}(\ln x)^{2}}{3}-\frac{2}{3} \int \ln x \cdot x^{2} d x \\ =\frac{x^{3}(\ln x)^{2}}{3}-\frac{2}{3}\left[\ln x \int x^{2} d x-\int\left\{\frac{d}{d x}(\ln x) \int x^{2} d x\right] d x\right] \\ =\frac{x^{3}(\ln x)^{2}}{3}-2 / 3\left[\frac{x^{3} \ln x}{3}-\frac{1}{3} \int x^{2} d x\right] \\ =\frac{x^{3}(\ln x)^{2}}{3}-\frac{2}{9} x^{3} \ln x-\frac{2}{9} \cdot \frac{1}{3} x^{3} \end{array}

=x3{(lnx)2329lnx227}+c =x^{3}\left\{\frac{(\ln x)^{2}}{3}-\frac{2}{9} \ln x-\frac{2}{27}\right\}+c

UV আকারের (Integration by parts) টপিকের ওপরে পরীক্ষা দাও