The slope of the line connecting two points (<em>a</em>, <em>b</em>) and (<em>c</em>, <em>d</em>) is
(<em>d</em> - <em>b</em>) / (<em>c</em> - <em>a</em>)
i.e. the change in the <em>y</em>-coordinate divided by the change in the <em>x</em>-coordinate. For a function <em>y</em> = <em>f(x)</em>, this slope is the slope of the secant line connecting the two points (<em>a</em>, <em>f(a)</em> ) and (<em>c</em>, <em>f(c)</em> ), and has a value of
(<em>f(c)</em> - <em>f(a)</em> ) / (<em>c</em> - <em>a</em>)
Here, we have
<em>f(x)</em> = <em>x</em> ²
so that
<em>f</em> (1) = 1² = 1
<em>f</em> (1.01) = 1.01² = 1.0201
Then the slope of the secant line is
(1.0201 - 1) / (1.01 - 1) = 0.0201 / 0.01 = 2.01
