第1个回答 2015-03-24
y = f(x,t),
t = t(x,y).
x是自变量,y,t都是因变量。
dy/dx = f'(x) + f'(t)dt/dx,
F(x,y,t) = 0.
F'(x) + F'(y)dy/dx + F'(t)dt/dx = 0,
dt/dx = [F'(x) + F'(y)dy/dx]/[-F'(t)].
dy/dx = f'(x) + f'(t)dt/dx = f'(x) + f'(t)[F'(x) + F'(y)dy/dx]/[-F'(t)],
[-F'(t) - f'(t)F'(y)]dy/dx = f'(t)F'(x) - f'(x)F'(t),
dy/dx = [f'(x)F'(t) - f'(t)F'(x)]/[F'(t) + f'(t)F'(y)]
证毕。本回答被提问者采纳