急,求不定积分∫ln(x²+1)dx ∫下面是0 上面是3

∫(0→3) ln(x² + 1) dx
= [x * ln(x² + 1)](0→3) - ∫(0→3) x d[ln(x² + 1)]
= 3ln(10) - ∫(0→3) x * 2x/(x² + 1) dx
= 3ln(10) - 2∫(0→3) [(x² + 1) - 1]/(x² + 1) dx
= 3ln(10) - 2∫(0→3) [1 - 1/(x² + 1)] dx
= 3ln(10) - 2[x - arctan(x)](0→3)
= 3ln(10) - 6 + 2arctan(3)