diff --git a/maximumsAndMinimums/exercises/maxMinTrueFalse9.tex b/maximumsAndMinimums/exercises/maxMinTrueFalse9.tex
index a0a3d0ece..27ad07963 100644
--- a/maximumsAndMinimums/exercises/maxMinTrueFalse9.tex
+++ b/maximumsAndMinimums/exercises/maxMinTrueFalse9.tex
@@ -11,7 +11,7 @@
 
 	If $f$ is differentiable and decreasing on $(a,b)$, then $f'(x)<0$ on $(a,b)$
 	\begin{hint}
-Think of $f(x)=-x^3$ on $(-1,1)$. $f$ is differentiable and decreasing, but $f'(0)=0$.
+Think of $f(x)=-x^3$ on $(-1,1)$. $f$ is differentiable and decreasing, but $f'(0)=0$. So the conclusion should be $f'(x)\leq 0$ on $(a,b)$. 
 \end{hint}	
 	\begin{multipleChoice}	
 		\choice{True}