| du | du | du | ||||
a) | +x2 | +z | =0 | |||
| dx | dy | dz |
| x | du | du | du | du | ||||||
b) | + (1−y2) | + (1−yz) | +(1−yv) | =0 | ||||||
| y | dx | dy | dz | dv |
| dx | dy | dz | ||||
a) | = | = | ||||
| 1 | x2 | z |
| dz | ||
dx= | ||
| z |
| ex | |
=C3 | |
| z |
| ex | ||
u(x,y,z)=F(x3−3y ; | ) | |
| z |
| ydx | dy | dz | dv | |||||
b) | = | = | = | |||||
| x | 1−y2 | 1−yz | 1−yv |
| dx | dy | ||
= | |||
| xy | 1−y2 |
| dx | dy | ||
= | |||
| x | y(1−y2) |
| 1 | 1 | |||
ln|x|=ln|y|+ | ln|1+y|− | ln|1−y|+c | ||
| 2 | 2 |
| x | 1−y | |||
ln|( | )2 | |=c | ||
| y | 1+y |
| d(z−v) | dy | ||
= | |||
| −y(z−v) | 1−y2 |
| d(z−v) | −y dy | |||
∫ | =∫ | |||
| (z−v) | 1−y2 |
| 1 | ||
ln|z−v|= | ln|1−y)(1+y)|+c2 | |
| 2 |
| (z−v)2 | ||
ln| | |=C3 | |
| (1−y)(1+y) |