What is the difference between $dy$ and $Δy$ and why is $dx$ is same as . . . For examples, this $\mathrm {d}y$ as $\delta y$ and $\mathrm {d}x$ as $\delta x$ notation is used in videos like the ones mentioned in a comment by the OP Yashasv Prajapati: blackpenredpen 's “ delta y vs dy (differential) ” and The Math Sorcerer 's “ How to Compute Delta y and the Differential dy ”
In differential calculus, why is dy dx written as d dx ( y)? In differential calculus, We know that dy dx is the ratio between the change in y and the change in x In other words, the rate of change in y with respect to x Then, why is dy dx written as d dx