∫sin[(x)^(1/2)]dx怎么做,
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∫sin[(x)^(1/2)]dx怎么做,
∫sin[(x)^(1/2)]dx怎么做,
∫sin[(x)^(1/2)]dx怎么做,
换元
√x=t t²=x
有dx=2tdt
带入
∫sin(√X)dx=∫2tsintdt
=-2∫tdcost
=-2[tcost-∫costdt]
=-2[tcost-sint]+C
=-2√Xcos√X+2sin√X+C(C是常数)
令t=x^(1/2) x=t^2
原式=∫2tsintdt
=-2∫td(cost)
=-2[tcost-∫costdt]
=-2tcost+2sint
=-2x^(1/2)*cos[x^(1/2)]+2sin[x^(1/2)]
令(x)^(1/2)=t,则x=t^2 t≥0
原积分可化为∫sin[(x)^(1/2)]dx:∫sintdt^2
=2∫tsintdt
=-2∫tdcost
...
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令(x)^(1/2)=t,则x=t^2 t≥0
原积分可化为∫sin[(x)^(1/2)]dx:∫sintdt^2
=2∫tsintdt
=-2∫tdcost
分步积分法: =-2(tcost-∫costdt+C)
=-2(tcost-sint+C)
将原来的变量带入:∫sin[(x)^(1/2)]dx=-2(√xcos√x-sin√x)+C
收起
∫sin[(x)^(1/2)]dx