解一道贝努利方程y'+y=y^4(cosx-sinx)看不清楚,能发个大点的吗?

学习 时间:2026-04-04 18:56:26 阅读:2186
解一道贝努利方程y'+y=y^4(cosx-sinx)看不清楚,能发个大点的吗?

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独特的背包

丰富的钥匙

2026-04-04 18:56:26

y'+y=y^4(cosx-sinx)y'/y^4+y/y^4=cosx-sinx(-1/3)d(1/y^3)/dx+(1/y^3)=cosx-sinxd(1/y^3)/dx-3(1/y^3)=3(sinx-cosx)d(1/y^3)/dx-3(1/y^3)=01/y^3=Ce^3x设方程通解(1/y^3)=C(x)e^3xC'(x)e^3x=3(sinx-cosx)C'(x)=3√2sin(x-π/4)e^(-3x)C(x)=(-9√2/10)e^(-3x)[sin(x-π/4)+(1/3)cos(x-π/4)]+C通解为1/y^3=(-9√2/10)*[sin(x-π/4)+(1/3)cos(x-π/4)]+Ce^3x∫sin(x-π/4)e^(-3x)dx=(-1/3)∫sin(x-π/4)de^(-x)=(-1/3)e^(-3x)sin(x-π/4)+(1/3)∫e^(-3x)cos(x-π/4)dx=(-1/3)e^(-3x)sin(x-π/4)-(1/9)∫cos(x-π/4)de^(-3x)=(-1/3)e^(-3x)sin(x-π/4)+(-1/9)e^(-3x)cos(x-π/4)-(1/9)∫e^(-3x)sin(x-π/4)dx+C1(10/9)∫sin(x-π/4)e^(-3x)dx=(-1/3)e^(-x)*[-sin(x-π/4)-(1/3)cos(x-π/4)]+C1∫sin(x-π/4)e^(-x)dx=(-3/10)e^(-x) *[sin(x-π/4)+(1/3)cos(x-π/4)]+C

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  • 霸气的冰淇淋
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    2026-04-04 18:56:26

    y'+y=y^4(cosx-sinx)y'/y^4+y/y^4=cosx-sinx(-1/3)d(1/y^3)/dx+(1/y^3)=cosx-sinxd(1/y^3)/dx-3(1/y^3)=3(sinx-cosx)d(1/y^3)/dx-3(1/y^3)=01/y^3=Ce^3x设方程通解(1/y^3)=C(x)e^3xC'(x)e^3x=3(sinx-cosx)C'(x)=3√2sin(x-π/4)e^(-3x)C(x)=(-9√2/10)e^(-3x)[sin(x-π/4)+(1/3)cos(x-π/4)]+C通解为1/y^3=(-9√2/10)*[sin(x-π/4)+(1/3)cos(x-π/4)]+Ce^3x∫sin(x-π/4)e^(-3x)dx=(-1/3)∫sin(x-π/4)de^(-x)=(-1/3)e^(-3x)sin(x-π/4)+(1/3)∫e^(-3x)cos(x-π/4)dx=(-1/3)e^(-3x)sin(x-π/4)-(1/9)∫cos(x-π/4)de^(-3x)=(-1/3)e^(-3x)sin(x-π/4)+(-1/9)e^(-3x)cos(x-π/4)-(1/9)∫e^(-3x)sin(x-π/4)dx+C1(10/9)∫sin(x-π/4)e^(-3x)dx=(-1/3)e^(-x)*[-sin(x-π/4)-(1/3)cos(x-π/4)]+C1∫sin(x-π/4)e^(-x)dx=(-3/10)e^(-x) *[sin(x-π/4)+(1/3)cos(x-π/4)]+C

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