So you could draw a tangent to the curve at the point and measure its slope using .
You could also choose another point very close to 2, say 2.001, and work out the slope of the line that would cross the two points, using . This will give you a good approximation.
Using calculus, if a function , its derivative (rate of change at any point) is given by . Substitute into the derivative and this will be the slope of the curve at that point.