함수 $u(x,y)$ 가 연속 편미분(derivative)이 있다면 그 '''전미분(total differential)'''은
 $du=\frac{\partial u}{\partial x}dx+\frac{\partial u}{\partial y}dy$

----
$\operatorname{d}f$ : total differential of $f$
 $\operatorname{d}f(x,y,\cdots)=\frac{\partial f}{\partial x}\operatorname{d} x+\frac{\partial f}{\partial y}\operatorname{d}y+\cdots$
from https://people.engr.ncsu.edu/jwilson/files/mathsigns.pdf#page=23

----
이변수 연속 함수 $u=u(x,y)$ 에서
 ....
아무튼 그래서 '''total differential''' of $u:$
 $du=\frac{\partial u}{\partial x}dx+\frac{\partial u}{\partial y}dy$

'''principal part in the change in $u$'''로 불리기도 한다고.

http://www.math.odu.edu/~jhh/Volume-1.PDF p159-160
----
Up: [[미분,differential]] [[VG:편미분,partial_derivative]]
Compare: [[전미분,total_derivative]] (MERGE?)