Question

In problem 1 they have dy/dx = cotx^2
Thats just the derivative of the y function and not x, what happens to dx?

Answer 1

derivative of the y function with respect to your x variable. here, the only variable is x- so you are set

Answer 2

Oh, so when dy/dx = dy/ty / dx/dt I just ignor the dx/dt part?

Answer 3

if by that you mean dy/dx= dy/dt / dx/dt: then that's a case where you have each function x and y expressed in terms of t. therefore, if you take the derivative of y in terms of t, and divide it by the derivative of x in terms of t, its the same thing as dy/dx (y in terms of x)

Answer 4

So here I actually use that formula but since there is no dx/dt I just ignore it