Hi,

$\displaystyle y(t) * dy(t)/dt = x(t) * dx(t)/dt$

My textbook says the integral is:

$\displaystyle y^2(t) - x^2(t) = constant$.

The part I'm not sure about is how they can put $\displaystyle y(t)$ out of the integral sign, and just integrate $\displaystyle dy(t)/dt$, as $\displaystyle y(t)$ is a function of time.

Thanks.