What is the formula to calculate the slope of the line?

Answer 1

To find the slope of any line y = f(x) differentiate with respect to x: slope = dy/dx; the slope at any point can then be found by substituting the value of the x coordinate of that point.

If you mean how to find the slope of a straight line:

slope = change_in_y/change_in_x

Taking any two points on the line (x0, y0) and (x1, y1) this becomes:

slope = (y_of_first_point - y_of_second_point)/(x_of_first_point - x_of_second_point)

→ slope = (y1 - y0)/(x1 - x0)

As it doesn't matter which is chosen as the first point, the slope can also be written as:

slope = (y0 - y1)/(x0 - x1)

Answer 2

The slope of a straight line between any two points is the difference in the y co-ordinates divided by the difference in the x co-ordinates (in the same order).So if P = (a, b) and Q = (c, d) then the slope is (b - d)/(a - c) or (d - b)/(c - a).

Answer 3

If you know, or can calculate, the coordinates of two points on the line, call them (x1, y1) and (x2, y2), you can calculate the slope as:slope = (y2 - y1) / (x2 - x1)