We use differentiation to generally find the rate of change for a function. This could also be interpreted as finding the gradient of a curve. e.g. y = x ^ 2.
If you consider the curve, it has a different gradient at various points. We could draw a tangent at the point however a more accurate answer would be to differentiate.
There is a simple method to differentiate curves. We denote the differential of y as dy/dx.
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