--- a/sigmoidGradient.m
+++ b/sigmoidGradient.m
@@ -1,33 +1,12 @@
 function g = sigmoidGradient(z)
-%SIGMOIDGRADIENT returns the gradient of the sigmoid function
-%evaluated at z
-%   g = SIGMOIDGRADIENT(z) computes the gradient of the sigmoid function
-%   evaluated at z. This should work regardless if z is a matrix or a
-%   vector. In particular, if z is a vector or matrix, you should return
-%   the gradient for each element.
-
-g = zeros(size(z));
-
-% ====================== YOUR CODE HERE ======================
-% Instructions: Compute the gradient of the sigmoid function evaluated at
-%               each value of z (z can be a matrix, vector or scalar).
-
-
-
+##SIGMOIDGRADIENT returns the gradient of the sigmoid function
+##evaluated at z
+##   g = SIGMOIDGRADIENT(z) computes the gradient of the sigmoid function
+##   evaluated at z. This should work regardless if z is a matrix or a
+##   vector. In particular, if z is a vector or matrix, you should return
+##   the gradient for each element.
 
-
-
-
-
-
-
-
+  s = @(z) 1./(1 + exp(-z));
+  g = s(z).*(1 - s(z));
 
-
-
-% =============================================================
-
-
-
-
-end
+endfunction