Evaluate: ∫xddx(12x3+4x+5) dx
let,
I=∫xddx(12x3+4x+5)dx
udvdx=duvdx−vdudxu=xxdvdx=dxvdx−v∴∫xdvdx=∫dxvdx−vdx∫xdvdx=xv−∫vdx+kv=12x3+4x+5I=∫xddx(12x3+4x+5)dx=12x4+4x2+5x−∫(12x3+4x+5)dx+kI=12x4+4x2+5x−[3x4+2x2+5x]+CI=9x4+2x2+C