In the slope equation,the increase of x is divided to the increase of y.But I cannot understand,why we cannot use the increase of y is divide to the increase of x.Everyone said,the gradient of the tangent to the curve at a point is one over one,increase in y divided by increase in x,etc....But they cannot tell why the increase of Y divide by increase of X and why we cannot use the increase of x divided by increase of y.
Consider a constant function, for example. You would say that the slope equals zero in that case. For an arbitrary increase in x, the increase of y would be zero, so x/y would not be defined. It doesn't make sense that way considering that the slope is meant to increase when the increase of y is bigger along a constant difference in x.