# Concern regarding dy/dx

I am really frustrated over the dy/dx notations.For example,we are taught that it is not a ratio,just an operation performed on $$y=f(x)$$.Also why do people multiply something by $$dx$$.For example,$$t=1+x^2$$,then people use $$\frac{dt}{dx}=2x$$,then write $$dt=2x \times dx$$.But $$dx$$ is a differential of $$x$$.It can have larger values as well.Then why do poeple confuse del y with $$dy$$.$$dy=f'(x)\times dx$$ and del y is the change in $$y$$ in the function.

• Any help?I am still stuck Nov 8, 2020 at 17:41