∫(x-1)⼀(x^2+2x+3)dx的不定积分怎么求

2024-11-10 23:57:10
推荐回答(2个)
回答1:

∫(x-1)/(x²+2x+3)dx
=½∫(2x-2)/(x²+2x+3)dx
=½∫(2x+2-4)/(x²+2x+3)dx
=½∫(2x+2)/(x²+2x+3)dx - ½∫4/(x²+2x+3)dx
=½∫(2x+2)/(x²+2x+3)dx - 2∫1/(x²+2x+3)dx
=½∫d(x²+2x+3)/(x²+2x+3) - 2∫1/[(x+1)²+2]dx
=½ln|x²+2x+3| - ∫1/{[(x+1)/√2]²+1}dx + C
=½ln|x²+2x+3| - (√2)∫1/{[(x+1)/√2]²+1}d[(x+1)/√2] + C
=½ln|x²+2x+3| - (√2)arctan[(x+1)/√2] + C

回答2:

分母下变成(X-1)(X+3). ∫(x-1)/(x^2+2x+3)dx=∫1/(X+3)dx =ln(x+3)