diff --git a/src/optimise/optimisers.jl b/src/optimise/optimisers.jl
index 31d47c32..01a92a70 100644
--- a/src/optimise/optimisers.jl
+++ b/src/optimise/optimisers.jl
@@ -27,7 +27,7 @@ function rmsprop(p::Param; η::Real = 0.001, ρ::Real = 0.9, ϵ::Real = 1e-8)
   acc  = zeros(p.x)
   function ()
     @. acc = ρ * acc + (1 - ρ) * p.Δ^2
-    @. p.Δ *= η / (√acc + ϵ)
+    @. p.Δ *= η / √(acc + ϵ)
   end
 end
 
@@ -35,7 +35,7 @@ function adagrad(p::Param; η::Real = 0.01, ϵ::Real = 1e-8)
   acc = zeros(p.x) .+ ϵ
   function ()
     @. acc += p.Δ^2
-    @. p.Δ *= η / √acc
+    @. p.Δ *= η / √(acc + ϵ)
   end
 end
 
@@ -56,7 +56,7 @@ function adam(p::Param; η::Real = 0.001, β1::Real = 0.9, β2::Real = 0.999, ϵ
   function ()
     @. mt = β1 * mt + (1 - β1) * p.Δ
     @. vt = β2 * vt + (1 - β2) * p.Δ^2
-    @. p.Δ =  mt / (1 - β1p) / (√(vt / (1 - β2p)) + ϵ) * η
+    @. p.Δ =  mt / (1 - β1p) / √(vt / (1 - β2p) + ϵ) * η
     β1p *= β1
     β2p *= β2
   end