meili 发表于 2022-10-27 15:18:15

已知(x+ay)dx+ydy(x+y)2为某函数的全微分,a则等于()A.-1B.0C.1D.2

<p>问题:已知(x+ay)dx+ydy(x+y)2为某函数的全微分,a则等于()A.-1B.0C.1D.2
<p>答案:↓↓↓<p class="nav-title mt10" style="border-top:1px solid #ccc;padding-top: 10px;">刘天虎的回答:<div class="content-b">网友采纳  由(x+ay)dx+ydy(x+y)2为某函数的全微分,记该函数为f,则有:df=∂f∂xdx+∂f∂ydy,∂∂x∂f∂y=∂∂y∂f∂x,因此,∂f∂x=x+ay(x+y)2,∂f∂y=y(x+y)2∂∂y∂f∂x=∂∂yx+ay(x+y)2=a(x+y)2−2x+ay(x+y)3=(...
页: [1]
查看完整版本: 已知(x+ay)dx+ydy(x+y)2为某函数的全微分,a则等于()A.-1B.0C.1D.2