How Do You Solve for At Using Subscript Derivative Notation?

  • Context: Undergrad 
  • Thread starter Thread starter Abdul.119
  • Start date Start date
  • Tags Tags
    Derivative Notation
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
1 reply · 2K views
Abdul.119
Messages
73
Reaction score
2
I have an equation that looks like

At, r = Aφ, r

If I know that Aφ = r4 , then how do I find At ?

I believe that the above equation is equivalent to: ∂/∂r (At) = ∂/∂r (Aφ) , correct?

Then substitute the value Aφ and we have ∂/∂r (At) = ∂/∂r (r4)

And then to get At I take the integral on both sides? so eventually At = r5/5 ?
 
Physics news on Phys.org
Abdul.119 said:
I have an equation that looks like

At, r = Aφ, r

If I know that Aφ = r4 , then how do I find At ?

I believe that the above equation is equivalent to: ∂/∂r (At) = ∂/∂r (Aφ) , correct?
Yes, ##A_{t, r}## is notation that means ##\frac{\partial}{\partial r}\frac{\partial A}{\partial t}##
Abdul.119 said:
Then substitute the value Aφ and we have ∂/∂r (At) = ∂/∂r (r4)

And then to get At I take the integral on both sides?
Yes. Integrate with respect to r.
Abdul.119 said:
so eventually At = r5/5 ?
Are r and t independent of each other. If so, the above looks fine.