Is this line rising or declining?

Question

Suppose, the white line in the picture (681x262 px) has the slope of 0.8107.

And, suppose, (0,0) is at the upper left.

Is it rising or declining?

What factors determine this decision?

Answer 1

There is something incomplete or misleading about this question.

The ``standard'' coordinate frame for the plane has the $x$ axis oriented left to right and the $y$ axis oriented from bottom to top of the page. In this case the slope $\frac{\Delta y}{\Delta x}$ of the white line should be positive, since there is a positive change in $y$ over a positive change in $x$.

In order for your line to have negative slope, something must be funny about how the (unstated) coordinate axes were defined in the figure. For example, in some computer graphics applications the $y$ axis is inverted, so that it is oriented from top to bottom and the origin is at the top-left of the page, in which case your line would indeed have negative slope.