∫xdx⼀(√(1+x^(2⼀3))) 详细过程!!谢谢大家了!!!

2024-12-29 04:02:53
推荐回答(1个)
回答1:

解:设x=tan³t,则dx=3tan²t*sec²tdt,cost=1/√(1+x^(2/3))
∴原式=∫tan³t*3tan²t*sec²tdt/sect
=3∫(tant)^5*sectdt
=3∫(sint)^5/(cost)^6dt
=-3∫(sint)^4/(cost)^6d(cost)
=-3∫(1-cos²t)²/(cost)^6d(cost)
=-3∫[1/(cost)^6-2/(cost)^4+1/cos²t]d(cost)
=-3[(-1/5)/(cost)^5+(2/3)/cos³t-1/cost]+C (C是积分常数,cost=1/√(1+x^(2/3)))