Faraday's Law Equation: Derivative vs Delta

[ManfredArcane]

My textbook gives the equation for Faraday's Law as ε=-(dΦ_B)/(dt) , the derivative of magnetic flux with respect to time. I have also seen Faraday's law expressed as ε= -(ΔΦ_B)/(Δt). Are these two forms equivalent? Thanks!

 

[anuttarasammyak]

You can take them equivalent.

 

[Ibix]

The latter is an approximation to the former. It's only valid when the rate of change is constant, or close enough that you don't care.