∫x√(ax+b)dx=

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∫x√(ax+b)dx=
∫x√(ax+b)dx=

∫x√(ax+b)dx=
∫x√(ax+b)dx
=1/a ∫x√(ax+b)d(ax+b)
=2/3a ∫xd(ax+b)^(3/2)
=2/(3a)[x(ax+b)^(3/2)-∫(ax+b)^(3/2)dx]
=2/3a*x(ax+b)^(3/2)-2/(3a^2)∫(ax+b)^(3/2)d(ax+b)
=2/(3a)*x(ax+b)^(3/2)-4/(15a^2)*(ax+b)^(5/2)+C
如有不懂科追问.

令√(ax+b)=t
x=(t^2-b)/a
dx=2t/adt
∫x√(ax+b)dx
=∫(t^2-b)/a*t*2t/adt
=2t^5/(5a^2)-2bt^3/(3a^2)+C

2
2

∫x√(ax+b)dx
=(2/3a)∫x/[(ax+b)^(3/2)]′dx
=(2/3a)∫xd[(ax+b)^(3/2)]
=(2x/3a)[(ax+b)^(3/2)]-(2/3a)∫[(ax+b)^(3/2)]dx
=(2x/3a)[(ax+b)^(3/2)]-(2/3a)(2a/5)[(ax+b)^(5/2)]+C
=(2x/3a)[(ax+b)^(3/2)]-(4/15a²)[(ax+b)^(5/2)]+C

这种无理函数的积分,解法是:
√(ax+b)=t ax+b=t^2, x=(t^2-b)/a dx=2t/a,代入:
∫x√(ax+b)dx
=∫(t^2-b)/a*t*2t/a
=(2/a^2)∫(t^4-bt^2)dt
=(2/a^2)∫(t^5/5-bt^3/3)+C
=(2/(15a^2))(√(ax+b))^3(3ax-2b)+C