equation Definition and 105 Threads

What is the difference between these two concepts? An equation is said to be "invariant" under some operation if the form of the equation doesn't change. However, isn't that exactly what "covariance" in physical laws means—that the form of the laws remains unchanged when applying an operation to...

Hi. If I write any random equation in 2D then the graph undoubtedly shows up on that 2D graphing system. Equation example: ##x^2 y^2 + x^2 y + x y =1## My question is: if I take the same equation: ##x^2 y^2 + x^2 y + x y =1## and if I manipulate the equation by including another variable...

Hi. I don´t know if this question should be in the maths forum, but as it´s related with circuit analysis, I will post it here. I just would like to know how you get: v(t) = 1/C ∫tt0 i(τ) dτ + v(t0) From: v(t)=1/C ∫t-∞ i(τ) dτ I just know the basics of calculus and I don´t know how to...

I am confused with the equation to be used for capacitor in electrical analysis The standard equation we have is Q=CV -> 1 the other equation is is V = Z*I ohms law Z is the impedance of the capacitor. Both are giving me voltage, which one to use ?

I encountered a problem in reading Phys.Lett.B Vol.755, 367-370 (2016). I cannot derive Eq.(7), the following snapshot is the paper and my oen derivation, I cannot repeat Eq.(7) in the paper. ##g^{\mu\nu}## is diagonal metric tensor and##g^{\mu\mu}## is the function of ##\mu## only...