diff --git a/lstm.py b/lstm.py
index b99bfa8..eb6a9ed 100644
--- a/lstm.py
+++ b/lstm.py
@@ -95,13 +95,13 @@ def bottom_data_is(self, x, s_prev = None, h_prev = None):
         self.state.f = sigmoid(np.dot(self.param.wf, xc) + self.param.bf)
         self.state.o = sigmoid(np.dot(self.param.wo, xc) + self.param.bo)
         self.state.s = self.state.g * self.state.i + s_prev * self.state.f
-        self.state.h = self.state.s * self.state.o
+        self.state.h = np.tanh(self.state.s) * self.state.o
 
         self.xc = xc
     
     def top_diff_is(self, top_diff_h, top_diff_s):
         # notice that top_diff_s is carried along the constant error carousel
-        ds = self.state.o * top_diff_h + top_diff_s
+        ds = self.state.o * top_diff_h * tanh_derivative(self.state.s) + top_diff_s
         do = self.state.s * top_diff_h
         di = self.state.g * ds
         dg = self.state.i * ds