# Closed form?

closed form??

let $$f:u \rightarrow R^n$$ be a differentiable function with a differentiable inverse $$f^{-1}: f(u) \rightarrow R^n$$. if every closed form on u is exact, show that the same is true for f(u).

Hint: if dw=0 and $$f^{\star}w = d\eta,$$ consider $$(f^{-1})^{\star}\eta.$$

i don't know where to start with the problem. what is a closed form? what does it mean that "every closed form on u is exact"?

Related Introductory Physics Homework Help News on Phys.org
HallsofIvy
One question you didn't ask: what is $$f^{\star}$$?