Integration of ax3+ bx / x4+ c2dx

we can writeax3+bxx4+c2dx=ax3x4+c2dx+bxx4+c2dxConsider the integral   ax3x4+c2dx  firstLet  x4+c2=u4x3 dx= du Therefore, ax3x4+c2dx =a41udu=a4lnu+C1=a4lnx4+c2+C1     As, 1xdx=lnxNow consider the integral  bxx4+c2dx let x2=v2x dx= dvTherefore, bxx4+c2dx=b21v2+c2dv=b2ctan-1vc+C2        As, ax2+a2dx=tan-1xa=b2ctan-1x2c+C1Hence, we can writeax3+bxx4+c2dx=ax3x4+c2dx+bxx4+c2dx =a4lnx4+c2+C1 + b2ctan-1x2c+C1=a4lnx4+c2 +b2ctan-1x2c+C        (Where, C1+C2=C)

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