dy x dt That tells us dx is x prime of t dt.

是y’dt，dy，becomes，y，prime，of，t，dt。,是x，So，，we，know，x，is，x，of，t。,它告诉我们dx是x

youdao

We have the integral from minus infinity to plus infinity of F(x)*x*dx, and that's really--you see it's the same thing because an integral is analogous to a summation.

我们用从负无穷到正无穷的积分公式F(x)*x*dx,你看到的，这是相同的事，因为积分是类似的求和过程。

youdao

dxdy So that's just x. So, that means that du dv is x dx dy.

这个就是x，这就意味着dudv是x倍的。

youdao