diff --git a/instructions/exercise_4.tex b/instructions/exercise_4.tex
index 543fdf452316efe80194d2b1ecc936655d678f43..901bbe1bdd95ebfe775e23e82468fc115edb2ea5 100644
--- a/instructions/exercise_4.tex
+++ b/instructions/exercise_4.tex
@@ -229,7 +229,7 @@ in your command line/shell before executing your program.
 			\item Calculate the Hesse matrix once and store its value:
 			$$H_k= \nabla^2f(x_k)$$
 			\item Calculate the step size:
-			$$\alpha_k = \frac{\left\langle g_k, d_k\right\rangle}{\left\langle d_k, H_k \cdot d_k\right\rangle}$$
+			$$\alpha_k = -\frac{\left\langle g_k, d_k\right\rangle}{\left\langle d_k, H_k \cdot d_k\right\rangle}$$
 			\item Update the current position:
 			$$x_{k+1} = x_k +\alpha_k \cdot d_k$$
 			\item Calculate the next gradient: