some typos.

quarto/derivatives/mean_value_theorem.qmd

@@ -330,7 +330,7 @@ Let $f(x)$ be differentiable on $(a,b)$ and continuous on $[a,b]$. Then there ex
 This says for any secant line between $a < b$ there will be a parallel tangent line at some $c$ with $a < c < b$ (all provided $f$ is differentiable on $(a,b)$ and continuous on $[a,b]$).
 
 
-Figure @fig-mean-value-theorem illustrates the theorem. The orange line is the secant line. A parallel line tangent to the graph is guaranteed by the mean value theorem. In this figure, there are two such lines, rendered using red.
+Figure @fig-mean-value-theorem illustrates the theorem. The blue line is the secant line. A parallel line tangent to the graph is guaranteed by the mean value theorem. In this figure, there are two such lines, rendered using brown.
 
 
 ```{julia}